For all those that have issues with Youtube sound...
 

It seems to be a generic memory, or a Manila issue:

disabling Sense UI temporarily should give you back your sound in the YT app.

That's why I think it works for some, but not all, when soft-resetting: takes awhile for the memory usage to increase to the point where YT sound disappears.

Re: For all those that have issues with Youtube sound...
 

Actually the most common reason for Youtube sound breaking is people installing custom taskbars, dialers, etc that use old .dll's.

Re: For all those that have issues with Youtube sound...
 

On some 2.5 roms if you install any themed dialer, it affects the sound as well.

Re: For all those that have issues with Youtube sound...
 

Sure - but there are mucho complaints it seems on people using cooked roms that have seemingly stock icons. Seems to be common on both Mighty and Juicy's ROMs.

Definitely happens for me (without any added taskbar icons/dialer skins) on multiple roms from both those cats.

Re: For all those that have issues with Youtube sound...
 

I do recall using Energy ROM once when 2.5 was still a resource HOG and not being able to even open YouTube with an insufficient memory error. It's odd that it will run but no have enough memory to do sound. Just doesn't sound like that is what is causing it but it is definitely a possibility. Especially since I reread what you said about it working right after a soft reset but not a couple hours later once the pagepool has increased. To narrow it down, have you tried a ram sweep instead of a soft reset? If you do a ram sweep and it works then I would say you are correct. If it still does not work, there is something else going on.

Re: For all those that have issues with Youtube sound...
 

I will try - the workaround stands, though, for all those pulling their hair out. Another similar issue: "Not enough Storage Available to process..." when trying to open Opera. Usually happens when memory is 80% or above. Killing/Restarting sense usually fixes it.

Re: For all those that have issues with Youtube sound...
 

When I ran into the problem, I found a post that showed a registry key edit. The sound was instantly back...