Yeah, that's the problem. I got a warning on my 2nd account too. I'm not sure but, I think after part 5 of the story mode, they have some kind of checker or something in it, so if you play part 6 and beyond using "all challenge complete" they will give you warning. Also one hit kill in coop...
Maybe you can try this way:
1. Install the original apk version and log in using google, or you can transfer data if you already have one.
2. Close the game,open file explorer. Go to android > data > and back up the folder named com.bandainamco
3. Uninstall the original version and install the...