diff --git a/fixtures/ssr/src/components/LargeContent.js b/fixtures/ssr/src/components/LargeContent.js
index f5c8adb03e233..3b1fa7ea35b25 100644
--- a/fixtures/ssr/src/components/LargeContent.js
+++ b/fixtures/ssr/src/components/LargeContent.js
@@ -1,8 +1,4 @@
-import React, {
-  Fragment,
-  Suspense,
-  unstable_SuspenseList as SuspenseList,
-} from 'react';
+import React, {Suspense, unstable_SuspenseList as SuspenseList} from 'react';
 
 export default function LargeContent() {
   return (
diff --git a/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetInlineCodeStrings.js b/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetInlineCodeStrings.js
index 8c4a0a8e9a00a..4e7fb4b73f6fa 100644
--- a/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetInlineCodeStrings.js
+++ b/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetInlineCodeStrings.js
@@ -6,7 +6,7 @@ export const markShellTime =
 export const clientRenderBoundary =
   '$RX=function(b,c,d,e,f){var a=document.getElementById(b);a&&(b=a.previousSibling,b.data="$!",a=a.dataset,c&&(a.dgst=c),d&&(a.msg=d),e&&(a.stck=e),f&&(a.cstck=f),b._reactRetry&&b._reactRetry())};';
 export const completeBoundary =
-  '$RB=[];$RV=function(b){$RT=performance.now();for(var a=0;a<b.length;a+=2){var c=b[a],e=b[a+1];null!==e.parentNode&&e.parentNode.removeChild(e);var f=c.parentNode;if(f){var g=c.previousSibling,h=0;do{if(c&&8===c.nodeType){var d=c.data;if("/$"===d||"/&"===d)if(0===h)break;else h--;else"$"!==d&&"$?"!==d&&"$~"!==d&&"$!"!==d&&"&"!==d||h++}d=c.nextSibling;f.removeChild(c);c=d}while(c);for(;e.firstChild;)f.insertBefore(e.firstChild,c);g.data="$";g._reactRetry&&requestAnimationFrame(g._reactRetry)}}b.length=0};\n$RC=function(b,a){if(a=document.getElementById(a))(b=document.getElementById(b))?(b.previousSibling.data="$~",$RB.push(b,a),2===$RB.length&&(b="number"!==typeof $RT?0:$RT,a=performance.now(),setTimeout($RV.bind(null,$RB),2300>a&&2E3<a?2300-a:b+300-a))):a.parentNode.removeChild(a)};';
+  '$RB=[];$RV=function(a){$RT=performance.now();for(var b=0;b<a.length;b+=2){var c=a[b],e=a[b+1];null!==e.parentNode&&e.parentNode.removeChild(e);var f=c.parentNode;if(f){var g=c.previousSibling,h=0;do{if(c&&8===c.nodeType){var d=c.data;if("/$"===d||"/&"===d)if(0===h)break;else h--;else"$"!==d&&"$?"!==d&&"$~"!==d&&"$!"!==d&&"&"!==d||h++}d=c.nextSibling;f.removeChild(c);c=d}while(c);for(;e.firstChild;)f.insertBefore(e.firstChild,c);g.data="$";g._reactRetry&&requestAnimationFrame(g._reactRetry)}}a.length=0};\n$RC=function(a,b){if(b=document.getElementById(b))(a=document.getElementById(a))?(a.previousSibling.data="$~",$RB.push(a,b),2===$RB.length&&("number"!==typeof $RT?requestAnimationFrame($RV.bind(null,$RB)):(a=performance.now(),setTimeout($RV.bind(null,$RB),2300>a&&2E3<a?2300-a:$RT+300-a)))):b.parentNode.removeChild(b)};';
 export const completeBoundaryUpgradeToViewTransitions =
   '$RV=function(A,g){function k(a,b){var e=a.getAttribute(b);e&&(b=a.style,l.push(a,b.viewTransitionName,b.viewTransitionClass),"auto"!==e&&(b.viewTransitionClass=e),(a=a.getAttribute("vt-name"))||(a="_T_"+K++ +"_"),b.viewTransitionName=a,B=!0)}var B=!1,K=0,l=[];try{var f=document.__reactViewTransition;if(f){f.finished.finally($RV.bind(null,g));return}var m=new Map;for(f=1;f<g.length;f+=2)for(var h=g[f].querySelectorAll("[vt-share]"),d=0;d<h.length;d++){var c=h[d];m.set(c.getAttribute("vt-name"),c)}var u=[];for(h=0;h<g.length;h+=2){var C=g[h],x=C.parentNode;if(x){var v=x.getBoundingClientRect();if(v.left||v.top||v.width||v.height){c=C;for(f=0;c;){if(8===c.nodeType){var r=c.data;if("/$"===r)if(0===f)break;else f--;else"$"!==r&&"$?"!==r&&"$~"!==r&&"$!"!==r||f++}else if(1===c.nodeType){d=c;var D=d.getAttribute("vt-name"),y=m.get(D);k(d,y?"vt-share":"vt-exit");y&&(k(y,"vt-share"),m.set(D,null));var E=d.querySelectorAll("[vt-share]");for(d=0;d<E.length;d++){var F=E[d],G=F.getAttribute("vt-name"),\nH=m.get(G);H&&(k(F,"vt-share"),k(H,"vt-share"),m.set(G,null))}}c=c.nextSibling}for(var I=g[h+1],t=I.firstElementChild;t;)null!==m.get(t.getAttribute("vt-name"))&&k(t,"vt-enter"),t=t.nextElementSibling;c=x;do for(var n=c.firstElementChild;n;){var J=n.getAttribute("vt-update");J&&"none"!==J&&!l.includes(n)&&k(n,"vt-update");n=n.nextElementSibling}while((c=c.parentNode)&&1===c.nodeType&&"none"!==c.getAttribute("vt-update"));u.push.apply(u,I.querySelectorAll(\'img[src]:not([loading="lazy"])\'))}}}if(B){var z=\ndocument.__reactViewTransition=document.startViewTransition({update:function(){A(g);for(var a=[document.documentElement.clientHeight,document.fonts.ready],b={},e=0;e<u.length;b={g:b.g},e++)if(b.g=u[e],!b.g.complete){var p=b.g.getBoundingClientRect();0<p.bottom&&0<p.right&&p.top<window.innerHeight&&p.left<window.innerWidth&&(p=new Promise(function(w){return function(q){w.g.addEventListener("load",q);w.g.addEventListener("error",q)}}(b)),a.push(p))}return Promise.race([Promise.all(a),new Promise(function(w){var q=\nperformance.now();setTimeout(w,2300>q&&2E3<q?2300-q:500)})])},types:[]});z.ready.finally(function(){for(var a=l.length-3;0<=a;a-=3){var b=l[a],e=b.style;e.viewTransitionName=l[a+1];e.viewTransitionClass=l[a+1];""===b.getAttribute("style")&&b.removeAttribute("style")}});z.finished.finally(function(){document.__reactViewTransition===z&&(document.__reactViewTransition=null)});$RB=[];return}}catch(a){}A(g)}.bind(null,$RV);';
 export const completeBoundaryWithStyles =
diff --git a/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetShared.js b/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetShared.js
index aa8d4cf94c3db..91b3b72ad4a0a 100644
--- a/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetShared.js
+++ b/packages/react-dom-bindings/src/server/fizz-instruction-set/ReactDOMFizzInstructionSetShared.js
@@ -420,21 +420,24 @@ export function completeBoundary(suspenseBoundaryID, contentID) {
   if (window['$RB'].length === 2) {
     // This is the first time we've pushed to the batch. We need to schedule a callback
     // to flush the batch. This is delayed by the throttle heuristic.
-    const globalMostRecentFallbackTime =
-      typeof window['$RT'] !== 'number' ? 0 : window['$RT'];
-    const currentTime = performance.now();
-    const msUntilTimeout =
-      // If the throttle would make us miss the target metric, then shorten the throttle.
-      // performance.now()'s zero value is assumed to be the start time of the metric.
-      currentTime < TARGET_VANITY_METRIC &&
-      currentTime > TARGET_VANITY_METRIC - FALLBACK_THROTTLE_MS
-        ? TARGET_VANITY_METRIC - currentTime
-        : // Otherwise it's throttled starting from last commit time.
-          globalMostRecentFallbackTime + FALLBACK_THROTTLE_MS - currentTime;
-    // We always schedule the flush in a timer even if it's very low or negative to allow
-    // for multiple completeBoundary calls that are already queued to have a chance to
-    // make the batch.
-    setTimeout(window['$RV'].bind(null, window['$RB']), msUntilTimeout);
+    if (typeof window['$RT'] !== 'number') {
+      // If we haven't had our rAF callback yet, schedule everything for the first paint.
+      requestAnimationFrame(window['$RV'].bind(null, window['$RB']));
+    } else {
+      const currentTime = performance.now();
+      const msUntilTimeout =
+        // If the throttle would make us miss the target metric, then shorten the throttle.
+        // performance.now()'s zero value is assumed to be the start time of the metric.
+        currentTime < TARGET_VANITY_METRIC &&
+        currentTime > TARGET_VANITY_METRIC - FALLBACK_THROTTLE_MS
+          ? TARGET_VANITY_METRIC - currentTime
+          : // Otherwise it's throttled starting from last commit time.
+            window['$RT'] + FALLBACK_THROTTLE_MS - currentTime;
+      // We always schedule the flush in a timer even if it's very low or negative to allow
+      // for multiple completeBoundary calls that are already queued to have a chance to
+      // make the batch.
+      setTimeout(window['$RV'].bind(null, window['$RB']), msUntilTimeout);
+    }
   }
 }
 
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzStaticBrowser-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzStaticBrowser-test.js
index c52612c51ca4a..cf4a65821e44f 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzStaticBrowser-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzStaticBrowser-test.js
@@ -40,6 +40,7 @@ describe('ReactDOMFizzStaticBrowser', () => {
 
     // We need the mocked version of setTimeout inside the document.
     window.setTimeout = setTimeout;
+    window.requestAnimationFrame = setTimeout;
 
     patchMessageChannel();
     serverAct = require('internal-test-utils').serverAct;