Like I said, logging out of Chat fixed this issue.
Edit: It “fixes” it but if you log back into Chat, you’ll have to same issue. Like I said, it’s a workaround.
Anyone reading this should try it, it worked for me on both Android and iOS.
(No issues in PC/Steam, as I said.)
i had this bug yesterday.
i decided i wanna finally make use of my extra team slots, but since the new pc interface is so horrible i decided to do it on mobile,
but i kept steam gow open on my team list to be able to “quickly” “move” my existing teams to different slots by looking at what i got there…
the gow on mobile performed so badly i couldnt even pick up a troop from troop list to drag it into a team slot 
No issues on my s7 edge. been playing all my GW battles on my phone vs PC, since the enemy stats are vastly different on PC.
Works fine on my s7 edge gets laggy when i carpet bomb with dragon souls 10 games in a row but other than that its fine
Logging out of guild chat fixed the severe lag, confirmed
It worked great at first but right back to insane waiting to click another button and freeze