This definitely doesn’t cover all or probably even most of the timeouts; a lot of it seems to be due to Ludia’s backend issues.
BUT…something I noticed…
So I was in a battle, and my phone ran out of battery. Later, when I reopened JWA, the usual “You lost!” message was instead replaced with “Time out!”, with the score being 2-2.
I suspect this would explain the battles that suddenly timeout halfway through. The opposing player left the match, and after some time Ludia’s servers consider it a time out, probably in some attempt to save players who have lost matches due to connectivity issues in their end.