diff --git a/Model/Layout/LayoutPlugin.php b/Model/Layout/LayoutPlugin.php
index 6447582b..9bf4dd8e 100644
--- a/Model/Layout/LayoutPlugin.php
+++ b/Model/Layout/LayoutPlugin.php
@@ -77,14 +77,16 @@ public function afterGenerateElements(\Magento\Framework\View\Layout $subject):
             }
         }
 
-        /*
-         * Surface the cacheability of a page. This may expose things like page blocks being set to
-         * cacheable = false which makes the whole page uncacheable
-         */
-        if ($subject->isCacheable()) {
-            $this->response->setHeader("fastly-page-cacheable", "YES");
-        } else {
-            $this->response->setHeader("fastly-page-cacheable", "NO");
+        if (empty($this->response->getHeader('fastly-page-cacheable'))) {
+            /*
+             * Surface the cacheability of a page. This may expose things like page blocks being set to
+             * cacheable = false which makes the whole page uncacheable
+             */
+            if ($subject->isCacheable()) {
+                $this->response->setHeader("fastly-page-cacheable", "YES");
+            } else {
+                $this->response->setHeader("fastly-page-cacheable", "NO");
+            }
         }
     }
 
diff --git a/Test/Unit/Model/Layout/LayoutPluginTest.php b/Test/Unit/Model/Layout/LayoutPluginTest.php
index caa23ea9..a542418b 100644
--- a/Test/Unit/Model/Layout/LayoutPluginTest.php
+++ b/Test/Unit/Model/Layout/LayoutPluginTest.php
@@ -112,6 +112,7 @@ public function testAfterGenerateElements($cacheState, $layoutIsCacheable, $cach
          $staleErrorTtl = 0, $cacheControl = 'max-age=86400, public, s-maxage=86400'): void
      {
          $headerName = 'cache-control';
+         $cacheableHeaderName = 'fastly-page-cacheable';
 
          $this->layoutMock->expects($this->any()
          )->method('isCacheable'
@@ -132,11 +133,18 @@ public function testAfterGenerateElements($cacheState, $layoutIsCacheable, $cach
          if ($layoutIsCacheable && $cacheState && $cacheType == \Fastly\Cdn\Model\Config::FASTLY && $ttl > 0) {
              if (!empty($cacheControl)) {
                  $cacheControlHeader = new GenericHeader($headerName, $cacheControl);
-
-                 $this->responseMock->expects($this->once()
-                 )->method('getHeader'
-                 )->with($headerName
-                 )->will($this->returnValue($cacheControlHeader));
+                 $cacheableHeader = new GenericHeader($cacheableHeaderName, 'YES');
+
+                 $this->responseMock->expects($this->exactly(2))
+                     ->method('getHeader')
+                     ->withConsecutive(
+                         [$headerName],
+                         [$cacheableHeaderName]
+                     )
+                     ->willReturnOnConsecutiveCalls(
+                         $this->returnValue($cacheControlHeader),
+                         $this->returnValue($cacheableHeader)
+                     );
 
                  $this->configMock->expects($this->once()
                  )->method('getStaleTtl'
@@ -157,19 +165,27 @@ public function testAfterGenerateElements($cacheState, $layoutIsCacheable, $cach
                      $value = sprintf(', stale-while-revalidate=%s', $staleTtl);
                  }
 
-                 $this->responseMock->expects($this->exactly(2)
+                 // change to once since 'fastly-page-cacheable' is already set in this mock, so method won't set it again
+                 $this->responseMock->expects($this->once()
                  )->method('setHeader');
                  //->with($headerName, $cacheControl . $value, true);
 
              } else {
 
-                 $this->responseMock->expects($this->once()
-                 )->method('getHeader'
-                 )->with($headerName
-                 )->will($this->returnValue(false));
-
-                 $this->responseMock->expects($this->once()
-                 )->method('setHeader');
+                 $this->responseMock->expects($this->exactly(2))
+                     ->method('getHeader')
+                     ->withConsecutive(
+                         [$headerName],
+                         [$cacheableHeaderName]
+                     )
+                     ->willReturnOnConsecutiveCalls(
+                         $this->returnValue(false),
+                         $this->returnValue('NO')
+                     );
+
+                 // Removed because 'cache-control' is not set in this case and 'fastly-page-cacheable' is already set
+                 // in mock, so second setHeader is skipped
+                 //$this->responseMock->expects($this->once())->method('setHeader');
              }
          } else {
              $this->responseMock->expects($this->once()