2 bugs to note, both pertaining to the actual phone "app" on my 3GS, after installing iOS4.
1) (This happens intermittently) When I receive a call or go to check my voicemail, for some reason the screen goes blank and until the other person hangs up or the voicemail ends (or sometimes when i mash on the sleep button), I can't access the rest of the phone. The call/voicemail runs fine, it just disables the entire phone otherwise.
2) I entered into the Clock app (not sure if it pertains specifically to the clock app) and the green "Press to return to call" bar appeared at the top and the call timer was rapidly cycling random numbers. Note that I was not even remotely in a call at the time. And when i exited the app, the bar disappeared.
Has anyone else experienced anything like these two occurences?