Glad to see it's not just me!
Yes, data does stall completely to answer the question. I know that the CNA ROM doesn't have the same problem with GSM, however the USB port is completely non-functional in their latest ROM, and I prefer the EOS ROM!
Hopefully from those logs it is just a timing issue with the order things come back up after some signal loss situations, and an easy fix. Oddly enough though, I'm on the train now and haven't had to toggle data despite going through normally dodgy areas...