Yeah I was experiencing the same issue. I started last month and put in 200 hours so far, never had an issue with my vanilla android install during that whole time, nothing changed, and then the update dropped the other day and I'm constantly getting disconnected. Sometimes it says client tampering, sometimes it says I fainted while disconnecting even though there's no possible way for level 25 Pokemon to faint my level 100 Banette (hunting entei in route 48) but still somehow it kicks me back to the poke center like all 6 level 100s got knocked out by the random level 25s there.
You won't get any help from support, just an auto reply and they don't even seem to fully read what you write, that was my personal experience anyway, just redirect you to the client tampering article even if you've indicated that you've already read it and followed the suggestions there. I figure it's best to take a break and hope everyone else having these issues speaks up until they decide to stop immediately blaming their players and actually investigate to see if there's an issue on their end.
Everyone I've talked to who has had a similar experience knows what the client tampering page says, we've all read it, we all double checked everything.
Meh, hopefully it gets resolved. Best to play something else while they sort it out and all the complaints roll in.