diff --git a/web/src/components/Changes/Changes.tsx b/web/src/components/Changes/Changes.tsx
index 60a939014..460edf1b5 100644
--- a/web/src/components/Changes/Changes.tsx
+++ b/web/src/components/Changes/Changes.tsx
@@ -32,7 +32,7 @@ import { useHistory } from 'react-router-dom'
 import { useGet } from 'restful-react'
 import { isEqual, noop } from 'lodash-es'
 import { useStrings } from 'framework/strings'
-import { normalizeGitRef, type GitInfoProps } from 'utils/GitUtils'
+import { normalizeGitRef, type GitInfoProps, FILE_VIEWED_OBSOLETE_SHA } from 'utils/GitUtils'
 import { PullRequestSection, formatNumber, getErrorMessage, voidFn } from 'utils/Utils'
 import { DiffViewer } from 'components/DiffViewer/DiffViewer'
 import { useEventListener } from 'hooks/useEventListener'
@@ -176,7 +176,7 @@ export const Changes: React.FC<ChangesProps> = ({
     rawFileViews
       ?.filter(({ path, sha }) => path && sha) // every entry is expected to have a path and sha - otherwise skip ...
       .forEach(({ path, sha, obsolete }) => {
-        out.set(path || '', obsolete ? 'ffffffffffffffffffffffffffffffffffffffff' : sha || '')
+        out.set(path || '', obsolete ? FILE_VIEWED_OBSOLETE_SHA : sha || '')
       })
     return out
   }, [rawFileViews])
diff --git a/web/src/components/DiffViewer/DiffViewer.tsx b/web/src/components/DiffViewer/DiffViewer.tsx
index b63330910..b3bb7268d 100644
--- a/web/src/components/DiffViewer/DiffViewer.tsx
+++ b/web/src/components/DiffViewer/DiffViewer.tsx
@@ -61,7 +61,9 @@ import {
   getCommentLineInfo,
   createCommentOppositePlaceHolder,
   ViewStyle,
-  contentDOMHasData
+  contentDOMHasData,
+  getFileViewedState,
+  FileViewedState
 } from './DiffViewerUtils'
 import {
   CommentAction,
@@ -114,13 +116,14 @@ export const DiffViewer: React.FC<DiffViewerProps> = ({
 
   // file viewed feature is only enabled if no commit range is provided (otherwise component is hidden, too)
   const [viewed, setViewed] = useState(
-    commitRange?.length === 0 && diff.fileViews?.get(diff.filePath) === diff.checksumAfter
+    commitRange?.length === 0 &&
+      getFileViewedState(diff.filePath, diff.checksumAfter, diff.fileViews) === FileViewedState.VIEWED
   )
   useEffect(() => {
     if (commitRange?.length === 0) {
-      setViewed(diff.fileViews?.get(diff.filePath) === diff.checksumAfter)
+      setViewed(getFileViewedState(diff.filePath, diff.checksumAfter, diff.fileViews) === FileViewedState.VIEWED)
     }
-  }, [diff.fileViews, diff.filePath, diff.checksumAfter, commitRange])
+  }, [setViewed, diff.fileViews, diff.filePath, diff.checksumAfter, commitRange])
 
   const [collapsed, setCollapsed] = useState(viewed)
   useEffect(() => {
@@ -711,8 +714,7 @@ export const DiffViewer: React.FC<DiffViewerProps> = ({
               when={
                 !readOnly &&
                 commitRange?.length === 0 &&
-                diff.fileViews?.get(diff.filePath) !== undefined &&
-                diff.fileViews?.get(diff.filePath) !== diff.checksumAfter
+                getFileViewedState(diff.filePath, diff.checksumAfter, diff.fileViews) === FileViewedState.CHANGED
               }>
               <Container>
                 <Text className={css.fileChanged}>{getString('changedSinceLastView')}</Text>
diff --git a/web/src/components/DiffViewer/DiffViewerUtils.tsx b/web/src/components/DiffViewer/DiffViewerUtils.tsx
index 36a3ea001..faffcd443 100644
--- a/web/src/components/DiffViewer/DiffViewerUtils.tsx
+++ b/web/src/components/DiffViewer/DiffViewerUtils.tsx
@@ -19,6 +19,7 @@ import HoganJsUtils from 'diff2html/lib/hoganjs-utils'
 import { get } from 'lodash-es'
 import type { CommentItem, SingleConsumerEventStream } from 'components/CommentBox/CommentBox'
 import type { TypesPullReqActivity } from 'services/code'
+import { FILE_VIEWED_OBSOLETE_SHA } from 'utils/GitUtils'
 
 export enum ViewStyle {
   SIDE_BY_SIDE = 'side-by-side',
@@ -257,3 +258,28 @@ export function activitiesToDiffCommentItems(
       }) || []
   )
 }
+
+export enum FileViewedState {
+  NOT_VIEWED,
+  VIEWED,
+  CHANGED
+}
+
+export function getFileViewedState(
+  filePath: string,
+  fileSha: string | undefined,
+  views: Map<string, string> | undefined
+): FileViewedState {
+  if (!views || !views.has(filePath)) {
+    return FileViewedState.NOT_VIEWED
+  }
+
+  const viewedSHA = views.get(filePath)
+
+  // this case is only expected in case of pure rename - but we'll also use it as fallback.
+  if (fileSha === undefined || fileSha === '') {
+    return viewedSHA === FILE_VIEWED_OBSOLETE_SHA ? FileViewedState.CHANGED : FileViewedState.VIEWED
+  }
+
+  return viewedSHA === fileSha ? FileViewedState.VIEWED : FileViewedState.CHANGED
+}
diff --git a/web/src/utils/GitUtils.ts b/web/src/utils/GitUtils.ts
index e754cce37..df962333d 100644
--- a/web/src/utils/GitUtils.ts
+++ b/web/src/utils/GitUtils.ts
@@ -234,6 +234,8 @@ export const normalizeGitRef = (gitRef: string | undefined) => {
 export const REFS_TAGS_PREFIX = 'refs/tags/'
 export const REFS_BRANCH_PREFIX = 'refs/heads/'
 
+export const FILE_VIEWED_OBSOLETE_SHA = 'ffffffffffffffffffffffffffffffffffffffff'
+
 export function formatTriggers(triggers: EnumWebhookTrigger[]) {
   return triggers.map(trigger => {
     return trigger