AWM did not work perfectly with Opus 12. There are threads about it causing the same problems it causes now, going back to 2009. Also many threads on the internet about it, and it even has to exclude itself from handling another tool by the same developers who make it.
Quoting from Conflicts with tools that move, on-top or modify other windows
In any case, it should be tested to see if it's behind the problem, as it's a waste of time to investigate anything else until that is done, when it is known to cause problems.