Actually, on the contrary... It the testing I have been doing on the Thunderbolt, I notice a few things:
1. The Thunderbolt crashes immediately upon booting up in safe mode. All safe mode does is disable all non-core Android services from auto-running at boot. (You may test this by powering off your Thunderbolt, then upon powering it back on, hold down the Volume Down key when you see the Quietly Brilliant splash screen. Keep holding it down until you see 'Safe Mode' in the bottom left of the screen.))
2. The Thunderbolt will power cycle about 10 minutes after the Mobile IM service is stopped with an 80% accuracy.
Further pointing to an issue possible with the Mobile IM service conflicting with another service or protocol is that when I first got the Thunderbolt I was blocked out of the Mobile IM service. When I'd try to sign in to, say, Windows Live on Mobile IM, I would be taken to a My VZW Single Sign On (SSO) page. This is common for some Verizon services, but you rarely see it. When I tried to sign in with my My VZW credentials, the SSO would freeze and force close. Since MR1 I can now log into Mobile IM and the subsequent SSO page.
All this is just likely coincidence and conjecture, but its a theory, and a different angle. Mobile IM conflicting with a core process or protocol possibly?