N4 on T-mobile, drops 3G/4G signal after call disconnect

[svarshavchik]

Having an occasional problem. After a call ends, the signal bars drop to nothing for about a minute, and the phone can't make or receive calls. After about a minute, the phone shows a network signal again, and I can place or receive another call. Seems to be 3G/4G related. If I enable 2G-only mode, the problem appears to go away. Anyone else having the same problem?