My 8820 is doing the same thing and it started with my update to the latest OS for ATT. I have since upgraded to a "better" OS
The work around...for me at least, is to press <ALT>, <CAP>, H and it will show you pretty much all the IMEI, PIN and App versions you're running, but you don't get to scroll through all of the Java and other display screens that are typically following the RIM one.