Hi tenshinadela, can you provide a link to a page/video demonstrating this problem?

You can try the video here https://www.html5rocks.com/en/tutorials/track/basics/

tenshinadela said

You can try the video here https://www.html5rocks.com/en/tutorials/track/basics/

The first video? The titles work fine if I let it play through. If I click anywhere along the player progress bar while a subtitle is displayed, then there is a problem of the updated title not replacing the existing one. Is that what you see?

(I run Firefox 67.0.2 on Windows 10.)

Yes, you are correct. Apologize for not posting a clear description for this issue.

Just a side note: The System Details list shows you have a rather old Shockwave Flash 26.0 r0 plugin (current is 32.0.0.207 (32.0 r0; 2019/06/11))

Thanks. It looks like this bug was discovered during the beta of Firefox 67, but due to timing, was fixed only for Firefox 68 and later: Bug 1535005 - [webvtt] html5 video captions doesn't disappear after seeking back to a position with an other caption.

I checked in Firefox Developer Edition (version 68.0b6) and the problem does not occur there. So, I think we all just have to wait for Firefox 68.

That's great. Thank you I tested it on Firefox 68 and it worked fine.