Hello Blizz, it appears in the latest patch update, the region switch has now disabled the current region you’re logged into.
This is causing problems for me since i play 2 accounts in the same region. In order to switch now, i have to log into eu, switch back to us, then log in with my alt account.
Prior to this update all i had to do is hit switch region, choose us, then switch to my alt account.
This is on mobile android.
same here
cannot log into my other accounts on my google laptop that acts like a mobile android, stuck in the same one account after recent patch
Same here, using iOS. Already reported on the known issues thread, where about 3 others have said they have the same problem, but no acknowledgement from Blizzard yet. 
I have the same issue and it’s really a big deal for me since me and my gf are using the same iPad to play. And I’m sure I’m not the only one who does this kind of thing. Please fix this!