Hi All.
I have found this Bug related to the Forums and SubForums:
If you take a Forum and you turn it into Link in ACP > Sync. Management and, subsequently, you try to return from Link to Forum the change, it doesn't happen. It needs to make a forced passage turning the Link into Category before and, subsequently, to transform the Category in Forum.
See:
Forum 1 (Change to) > Link 1 ~ OK
Link 1 (Change to) > Forum 1 ~ Not OK. The change doesn't happen. Link 1 remain.
Solution
Link 1 (Change to) > Category 1 ~ OK
Category 1 (Change to) > Forum 1 ~ OK