wrong posts number on Advanced forum after attachment migration

I'm really not sure if this is a phpbb2drupal bug.

I don't see duplicate content on the front end, database is good and there aren't duplicates.
I think is simply an advanced forum's bug.

If I disable it, on core forum module post counts is identical to phpbb3, perfect.

I think advanced forum has problems with post count with nested forums, with many sub-forums and nested forums under containers (phpbb3 permits these things).

I can't explain, after disabling it and reenabling it now it says there are 17000 posts lol, they are around 4000 in the database :D
Advanced forum is saying that there are 12000 posts in a subforum, but that's clearly wrong, there are 1170 posts there in phpbb3 and core forum module shows same correct number.

The closest thing I can see in the database is that the biggest "comment ID" is about 17000 (because they start from 12xxx), maybe it's taking numbers from comment id/entity id #?

Sorry I can't post the forum, it's a private forum with sensible data and it's offline now.

I'm closing this for now because I don't think is this module's fault.

I'll try to do a better diagnose and I'll post there for sure.