Unfortunately, the fix suggested by fredriksthlm didn't change anything for me.
I found out that ANRs started with release r303 (and every release after that) and it probably has nothing to do with the updated Advert Mobile plugin, because it was only updated in r306.
Right now I'm checking my other theory - whether this is caused by changes with Splash screen (Scirra changed splash screen plugin in r303). I've built my game in r314, disabled the new splash screen and released this version today. In the next couple of days I'll see if this solves the problem.