We have just come across this problem. Running same version of Call Manager 8.0.3. We were using Remote Destination profiles for Mobility, but after starting to run Cisco Jabber on the iPhone, we set up the Mobile Identity as instructed in the Admin guide. Seems that sometime after the TCT device is registered in Call Manager and then moving off of the corporate network to the mobile carrier, calls to the office fail. The Cisco phone in the office rings, but when the call is answered you get a message from the mobile carrier about the call failing. Simply doing an "Apply Config" on the TCT device gets it working again, but this is a big headache when you can't call the office from the mobile carrier network.
I assume this is a bug. I found Bug CSCti23620 that seems to be close. Has anyone confirmed this is fixed in the version listed?