Replay integration breaks Help Scout beacon (iframe) in Safari

[pqvst]

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/vue

SDK Version

7.73

Framework Version

3.3.4

Link to Sentry event

No response

SDK Setup

Sentry.init({
  app,
  dsn: '...',
  integrations: [
    new Sentry.BrowserTracing(),
    new Sentry.Replay(),
  ],
  replaysOnErrorSampleRate: 1,
});

Steps to Reproduce

Enabling the Sentry.Replay plugin with replaysOnErrorSampleRate breaks our Help Scout beacon iframe in Safari.

• If I disable the Sentry.Replay plugin, it renders correctly.

• If I remove replaysOnErrorSampleRate it renders correctly.

• If I downgrade to Sentry 7.72 it renders correctly.

Expected Result

I expect Sentry to not interfere with the rendering of iframes.

Actual Result

Sentry 7.73:
For some reason the iframe seems to think it is bigger than it actually is. The iframe is still 60x60 but the inner content becomes too big.

Sentry 7.72:
The iframe functions correctly. The iframe is 60x60 and the inner content is correct.

[mydea]

If this worked in 7.72.0 but not in 7.73.0, it is most probably related to our upgrade of the underlying recording library, rrweb, from v1 to v2.

cc @billyvg can you take a look at that?

[billyvg]

Yep I'll see if I can create a repro with HelpScout.

[mydea]

Hey @pqvst ,

is your page publicly available? Or do you have a way to provide us with a reproduction, so we can dig into the cause here?

[pqvst]

@mydea No, but I managed to create a very minimal reproduction of the bug. You can download this HTML page and just open it locally in Safari:
https://github.com/pqvst/sentry-helpscout-beacon-bug/blob/main/repro.html

Furthermore, I was able to reproduce without any custom Sentry configuration.

There seems to be some timing factor, so somtimes you'll have to refresh the page a couple of times before the bug appears.

[billyvg]

@pqvst Can you try version 7.74.0? I suspect this issue may be related to #9234