Anecdotally, I was also on a train, then when I got to my destination (with good 3G), I found that the daemon was stuck at 100% cpu - killing and restarting sorted it out, but it had used a fair amount of battery on my train journey without me noticing, and hadn't fixed itself when back in an area of good reception.
I don't know how best to debug this, and whether it's a problem in Mitakuuluu or the Jolla networking implementation. Maybe stepping in and out of an elevator to simulate signal loss!

And also I still get the problem that Mitakuuluu thinks it's connected, but doesn't get messages. I have "Quit" set to the cover actions for this reason, and frequently restart in case a network transition has confused the daemon. So for me, the aggressive reconnect isn't even aggressive enough!
(Although the latest version hides the cover actions when not connected, so if it gets stuck when it thinks it's disconnected, I need to go in and quit with the pulley menu)

I should say (not for this thread to be wall-to-wall complaints) that otherwise Mitakuuluu is great, and the pace of development and bugfixes is impressive - many thanks to coderus!