Just installed 8.5, minutes ago. Testing things out. Went to youtube.com with the firefox browser. It's all "stock". i haven't updated yet. The machine is registered.
This also happens with other browsers, chrome, opera.... IMHO it must be something in the OS or GUI.
I start a youtube video. Right off the bat, the sound has static, and usually the sound also lags the video by 2-3 seconds. I'm using the HDMI output. I can sometimes clear this up by stopping all tabs, then clearing out everything in the browser history, exit FF and start back up. Usually the sound and picture are synced back up on FF restart. However, if I open a new FF window, and go to someplace like mouser.com (electronics parts place; it isn't running videos) the problem precipitates almost immediately.
I had this same problem under Centos 8.3 and others. I tried a bunch of parameters in FF to no avail. So, I figured, I must have too many personal configuration changes. So, here I am with a fresh 8.5 RHEL install, out of the box, no personal configs, and, boom. The problem is still here.
Any insights at all?