I tried to post a youtube video with a timestamp through the 'insert video' function in the forums. After fetching the video, the video would play the timestamp fine, but on subsequent attempts (before or after posting the post) the timestamp had dissapeared. Turns out that the timestamped URL immediatly gets replaced with a non-timestamped url as soon as i hit the insert button. (https://www.youtube.com/watch?v=Pjh1Uo_xaSQ). The timestamp only works the first time i insert & play the video in the preview window.
I'm on Firefox 73.0.1 (64 bit), Windows 10 1909