Comment 2 for bug 1409694

Sorry Tony.

Image is latest RTM build 191. On krillin. This has been happening over Xmas too so since 179 most likely. It looks like what happens is at some point the signal is dropped from sim1 and whether or not there is a sim in sim2 and not matter what state the sim is in, it is selected meaning you lose signal and therefore data. You can manually go into settings → cellular and switch to sim 1 the h disappears for a couple of seconds and then reappears once the sim1 is up and running and the data connection is then back up and running.

Jean-Baptised has seen this in France too so not generic to uk.