Session replay not rendering correctly on firefox

[Ulset]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/remix

SDK Version

8.17.0

Framework Version

Remix 2.10.2, vite 5.3.3

Link to Sentry event

https://weebe.sentry.io/replays/c9e15b13436d448d9c7df35cfd7ba445/?environment=staging&project=450748936572116

SDK Setup/Reproduction Example

import * as Sentry from "@sentry/remix";

Sentry.init({
  dsn: "https://edab7551bfaf9f75bb0d6ffb648fe960@o45074893631651.ingest.de.sentry.io/4507489365721168",
  integrations: [
    Sentry.browserTracingIntegration({
      useEffect
    }),
    // Replay is only available in the client
    Sentry.replayIntegration({
      maskAllText: false
    }),
  ],
  enabled: process.env.NODE_ENV !== "development",
  environment: process.env.NODE_ENV,
  tracesSampleRate: 1.0,
  // Capture Replay for 10% of all sessions,
  // plus for 100% of sessions with an error
  replaysSessionSampleRate: 1.0,
  replaysOnErrorSampleRate: 1.0,
})

Steps to Reproduce

1. Set up sentry session replay as according to the sentry for remix documentation.
2. Use the app
3. Watch replay. Observe that the rendering of the page is not updating correctly

Expected Result

This is the page on the app:

This is whats rendered on sentry.io:

As you can see it seems like sentry doesnt recognize that this was a new page render, and renders the new page at the bottom of the old one

Actual Result

[andreiborza]

Hello @Ulset thanks for filing this. At first glance, I can't really spot anything out of the ordinary with your setup. I'll pass this along to the replay team cc @billyvg.

[Ulset]

Hello! I might also add that ive used sentry for a few weeks now, and this havent been a issue until about 2-3 days ago! If you have access to see all my replays you can see that the session replay worked flawlessly earlier. Ive also not made any changes to the codebase that i think would effect sentry in any way

[Lms24]

I also think this needs eyes from the replay team but just to get some more details:

• are you using a UI library? If so, which one(s)?
• do you have any special setup on your web app like micro frontents/module federation, iframes, etc?
• since you mentioned this worked fine beforehand and only started happening recently: Did anything change in your app regarding CSS or layouts? Any chance you updated some dependencies?

[Ulset]

Hello!

• We use a mix of Polaris and Ant design, but we have made no changes to the UI elements priot to sentry having the render issues.
• Yes, the app runs in a iFrame
• Hmm yes actually i did update some dependencies and switched over to Vite around the same time