I have the same exact issue...going from reverse to drive the screen will go blank, but the radio will still work. I can get it back up with either hitting the power button once or twice, or turning the truck off/on. There are some more details in this thread:
Finally had mine updated. took about 40 minutes this time! So far cant tell a difference. Voice recognition is still inoperative - grayed out
5thgenrams.com
BernieR includes an attachment from a STAR Publication that states the issue won't be resolved until the next update in Q4. Something about data being received from the radio or a low voltage differential signal. It is likely that plus other software bugs that need to be worked out. Until then, this may be an annoyance/inconvenience we have to live with temporarily as people have tried to fix the problem other ways (hard reset, replace HD/memory unit), which didn't fix the problem or made things worse. So all they did was loose their truck for however long it took to "fix" the issue only to be right back where they started before taking it for service. From what I've read in the forums, sometimes these "updates" take half to a full day and new HD/memory units (I don't think they replace the whole screen unit) take weeks to come in.
A couple of other issues I have are intermittently dropping calls or I no longer transmit voice (other person can't hear me, but I hear them). However, over the grand scheme of things, I think these are glitches I can deal with until a better long term solution is released (hopefully). Until then, I'd rather continue enjoying the non-glitchy parts of my beautiful truck rather than let it sit in a service center.
This may be a more forgiving thought, but I think we need to realize that a complicated infotainment system that is incorporating so many different functions into one unit likely has hundreds of thousands (if not millions) of lines of code that are bound to have errors and there are likely unanticipated issues with how certain functions may interact with each other. Like anything else out there (video games, computers, phones, etc.) the patch/update process is always ongoing and improving, so the optimist in me thinks that eventually, albeit slowly, the updates should work things out. Although reluctantly, as much as I want the infotainment to be 100% bulletproof, I know it will never get there.