Yeah, seriously.
I thought it was limited to only native WinMo apps, dialers, and such, but then I noticed that after 30 seconds of inactivity, my screen turned itself off automatically when I was using TomTom as well.
When it does this, I also lose access to my Voice Navigation/Prompts (not just the screen itself).
This is totally unacceptable.
I've used all of the other MR's in the past, and none of them have ever had this problem.
I hard reset twice, before and after, and yet still this problem persists.
I decided to give it a couple of days to see if the problem resolves itself before posting, or at least until other people chime in, but I see little mention of it.
I can not use this ROM or recommend it to anyone else unfortunately until this problem is resolved.