I've noticed that every BBcode tag inside a quote generate an error. Smilies too.
I have to correct myself. Polishing the migrated post in the new punBB board from wrong codes (like: :a58714dfdf) the "tags in tags" runs OK, like in the phpBB original board: the problem, so, is during the migration only when the strange codes (:a58714dfdf) are added. The converter when founds a tag in tag post to migrate, add them and, of course, the migrated post appear with these additional characters.
Any suggestion will be greatly appreciated.