These are definately linked to Google Voice. I have had GV installed for only 3 days. No other Google apps installed, and I have seen the same certificate issue for the past 2 mornings. I clicked trust this am, so we will see how that works out tomorrow am.
It's been doing it to me too. I got the same IT policy what-not message when I tried to trust it which is weird since I am the original owner and it's been strictly for personal use. I don't even know of any local companies that use them on a BES.
And it's been popping up at random times. I usually see it after I've unlocked my phone though, not while I'm in the middle of something.
I was able to trust the Certificate by going to Option - Security Options - Advanced Security - Certificates and changing it there. Instead of having a check mark or 'x' by it, it now has a question mark.