diff --git a/docs/sentry.md b/docs/sentry.md
index 1fc232429..27a1ae607 100644
--- a/docs/sentry.md
+++ b/docs/sentry.md
@@ -20,25 +20,42 @@ Three independent checks. An event is dropped if **any** of them match.
 
 Sentry treats each string as a **substring**. `Failed to fetch` also matches `Failed to fetch dynamically imported module`.
 
-| You will stop seeing                                                                                                                                                 | Typical cause                                                                         |
-| -------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------- |
-| Handled unknown error                                                                                                                                                | Sentry could not extract a real Error from Angular                                    |
-| Non-Error promise rejection captured…                                                                                                                                | A promise rejected with `undefined` / `null` / a plain object                         |
-| no elements in sequence                                                                                                                                              | RxJS `EmptyError` (empty observable used with `first()` / `single()`)                 |
-| ResizeObserver loop…                                                                                                                                                 | Browser layout warning                                                                |
-| Failed to fetch                                                                                                                                                      | Chrome/Edge: offline, CORS, blocked request, including `api.osf.io` / `addons.osf.io` |
-| Load failed                                                                                                                                                          | Safari equivalent of failed fetch (including `files.osf.io`)                          |
-| NetworkError when attempting to fetch resource                                                                                                                       | Firefox equivalent of failed fetch                                                    |
-| Failed to fetch dynamically imported module / error loading dynamically imported module / Importing a module script failed / ChunkLoadError / Loading chunk … failed | User has an old tab open after a frontend deploy                                      |
-| AbortError / The operation was aborted / The user aborted a request                                                                                                  | Request cancelled (navigation, timeout, user abort)                                   |
+| You will stop seeing                                                | Typical cause                                                                         |
+| ------------------------------------------------------------------- | ------------------------------------------------------------------------------------- |
+| Handled unknown error                                               | Sentry could not extract a real Error from Angular                                    |
+| Non-Error promise rejection captured…                               | A promise rejected with `undefined` / `null` / a plain object                         |
+| no elements in sequence                                             | RxJS `EmptyError` (empty observable used with `first()` / `single()`)                 |
+| ResizeObserver loop…                                                | Browser layout warning                                                                |
+| Failed to fetch                                                     | Chrome/Edge: offline, CORS, blocked request, including `api.osf.io` / `addons.osf.io` |
+| Load failed                                                         | Safari equivalent of failed fetch (including `files.osf.io`)                          |
+| NetworkError when attempting to fetch resource                      | Firefox equivalent of failed fetch                                                    |
+| Failed to fetch dynamically imported module                         | Chrome/Edge: lazy chunk failed to load (often an old tab after deploy)                |
+| error loading dynamically imported module                           | Firefox: same lazy-chunk failure                                                      |
+| Importing a module script failed                                    | Safari: same lazy-chunk failure                                                       |
+| ChunkLoadError / Loading chunk … failed                             | Webpack/Vite chunk load failure after deploy                                          |
+| AbortError / The operation was aborted / The user aborted a request | Request cancelled (navigation, timeout, user abort)                                   |
+| Beacon is not defined                                               | Extension or third-party script; not OSF (`navigator.sendBeacon` is a different API)  |
 
 ### 2. Script URL (`denyUrls`)
 
-Errors whose stack frames come from a **browser extension**, not from OSF code (`chrome-extension://`, `moz-extension://`, `safari-extension://`, and similar).
+Errors whose stack frames come from a **browser extension**, not from OSF code:
+
+- `extensions/`
+- `chrome://`
+- `chrome-extension://`
+- `moz-extension://`
+- `safari-extension://`
+- `safari-web-extension://`
+- `ms-browser-extension://`
 
 ### 3. HTTP status below 500 (`beforeSend`)
 
-If the event is an HTTP response (Angular `HttpErrorResponse`, the message `Http failure response for …: 410`, or `Object captured as exception` with HTTP fields) and the status is **0–499**, it is dropped.
+If the event is an HTTP response and the status is **0–499**, it is dropped. Status is read from:
+
+- Angular `HttpErrorResponse` (including nested `ngOriginalError` / `rejection` / `cause`)
+- `Http failure response for …: 410`
+- `Server returned code 404 with body "…"`
+- `Object captured as exception with keys: …` or `Non-Error exception captured with keys: …` when the keys look like an HTTP response
 
 | Status        | Meaning                                | Dropped?            |
 | ------------- | -------------------------------------- | ------------------- |
diff --git a/src/app/core/helpers/sentry-filter.helper.ts b/src/app/core/helpers/sentry-filter.helper.ts
index 9bd53031f..230c11b9d 100644
--- a/src/app/core/helpers/sentry-filter.helper.ts
+++ b/src/app/core/helpers/sentry-filter.helper.ts
@@ -17,6 +17,7 @@ export const SENTRY_IGNORE_ERRORS: (string | RegExp)[] = [
   'The user aborted a request',
   'ChunkLoadError',
   /Loading chunk [\w.-]+ failed/,
+  'Beacon is not defined',
 ];
 
 export const SENTRY_DENY_URLS: (string | RegExp)[] = [