diff --git a/ui/src/components/filtering/utils.ts b/ui/src/components/filtering/utils.ts
index 82ce2f9a3..c22942cec 100644
--- a/ui/src/components/filtering/utils.ts
+++ b/ui/src/components/filtering/utils.ts
@@ -13,7 +13,7 @@ export const stringToBoolean = (string?: string) => {
 }
 
 export const booleanToString = (value?: boolean) =>
-  value !== undefined ? `${value}` : ''
+  value !== undefined && value !== null ? `${value}` : ''
 
 // Help function to decide if a filter section should be open or not on page load
 export const someActive = (
diff --git a/ui/src/data-services/hooks/deployments/utils.ts b/ui/src/data-services/hooks/deployments/utils.ts
index 8fd9c7d36..5c19b59a0 100644
--- a/ui/src/data-services/hooks/deployments/utils.ts
+++ b/ui/src/data-services/hooks/deployments/utils.ts
@@ -15,7 +15,8 @@ export const convertToFormData = (fieldValues: DeploymentFieldValues) => {
     research_site_id: fieldValues.siteId,
   }).forEach(([key, value]) => {
     if (value !== undefined) {
-      data.append(key, `${value}`)
+      // Convert null to empty string to signal "clear this field" (matches image field pattern)
+      data.append(key, value === null ? '' : `${value}`)
     }
   })
 
diff --git a/ui/src/data-services/models/deployment-details.ts b/ui/src/data-services/models/deployment-details.ts
index 85fd75770..8137c8562 100644
--- a/ui/src/data-services/models/deployment-details.ts
+++ b/ui/src/data-services/models/deployment-details.ts
@@ -11,8 +11,8 @@ export type ServerNestedCapture = {
 
 export interface DeploymentFieldValues {
   dataSourceId?: string
-  dataSourceSubdir?: string
-  dataSourceRegex?: string
+  dataSourceSubdir?: string | null
+  dataSourceRegex?: string | null
   description: string
   deviceId?: string
   name: string
@@ -68,11 +68,11 @@ export class DeploymentDetails extends Deployment {
     }
   }
 
-  get dataSourceSubdir(): string {
+  get dataSourceSubdir(): string | null {
     return this._deployment.data_source_subdir
   }
 
-  get dataSourceRegex(): string {
+  get dataSourceRegex(): string | null {
     return this._deployment.data_source_regex
   }
 
diff --git a/ui/src/pages/deployment-details/deployment-details-form/section-source-images/section-source-images.tsx b/ui/src/pages/deployment-details/deployment-details-form/section-source-images/section-source-images.tsx
index 2d6c17bf0..1b6d8763b 100644
--- a/ui/src/pages/deployment-details/deployment-details-form/section-source-images/section-source-images.tsx
+++ b/ui/src/pages/deployment-details/deployment-details-form/section-source-images/section-source-images.tsx
@@ -91,7 +91,7 @@ export const SectionSourceImages = ({
           <ConnectionStatus
             storageId={deployment.dataSource.id}
             subdir={deployment.dataSourceSubdir ?? ''}
-            regex={deployment.dataSourceRegex}
+            regex={deployment.dataSourceRegex ?? ''}
             showDetails
             onConnectionChange={setIsConnected}
           />
diff --git a/ui/src/utils/getAppRoute.ts b/ui/src/utils/getAppRoute.ts
index 2bb12d398..db9ee534e 100644
--- a/ui/src/utils/getAppRoute.ts
+++ b/ui/src/utils/getAppRoute.ts
@@ -26,7 +26,7 @@ export const getAppRoute = ({
     keepSearchParams ? window.location.search : undefined
   )
   Object.entries(filters).forEach(([name, value]) => {
-    if (value !== undefined) {
+    if (value !== undefined && value !== null) {
       searchParams.set(name, value)
     }
   })