[Intermittent] The immersive mode on-screen controls can no longer be displayed after repeatedly clicking on the Skip forward 30s/Skip back 10s buttons before playing a video

[heres-maria-sv-inactive]

[Affected Versions]:

• Firefox Reality version 8-33472001 (6ba3881)

[Affected Platforms]:

• Oculus Quest - Android 7.1.1
• HTC Vive Focus Plus - Android 7.1.2

[Prerequisites]:

• The headset is turned on and the browser is opened.
• Make sure to have “Autoplay Media” turned off.

[Steps to reproduce]:

1. Go to a YouTube video, but do not play it.
2. Enter immersive mode.
3. Press the trigger button to display the on-screen controls.
4. Click the Skip 30s button a few times.

[Expected results]:

• The video skips ahead 30s for each time it is clicked.

[Actual results]:

• The on-screen controls are no longer displayed and can not be triggered anymore.

[Notes]

• The issue is reproducible if clicking the Skip back 10s button as well.
• The issue is reproducible for videos that have immersive mode opened from theater mode as well as those that automatically open in immersive mode.
• On Oculus devices immersive mode blacks out, while on HTC devices it is frozen in the initial state.
• The issue was not reproducible on websites other than YouTube (e.g. Veoh, The Internet Archive’s movie section).
• Needed by [meta] Improve YouTube experience #1760.
• Attached is a recording of the issue.