I would like to point out that after re-reading the first responses again I still do not see it answering the issue, at least not as fully as would be required for someone like myself that has used phpBB for years and never had any issues. I had done what was explained in that first point but didn't know I had to jump to the thought that it was the Global Moderator group being moderated.... That little bit of logic might seem understandable for some but it is interesting in my mind.
Believe me I have tried all the different ways to change the permissions for the Global Moderator group forum based permissions - But it appears that due to the layout / structure of the forum I am forced to do each element one after the other.
You apparently have forums where the Global Moderator group does not have the specific permission that they can post without approval. Prior to 3.0.12 that didn't matter because someone able to approve posts in a forum was also able to post in it without approval without having that specific permission. That was subsequently considered to be a fault and so was fixed in 3.0.12.
On most boards it was not an issue because the Global Moderators are, by default, also in the Registered Users group which usually has a forum permission role which allows members to post without approval.
If your Global Moderators are not in the Registered Users group the simplest fix is probably just to add them to that group.
For any particular board we have no way of knowing which groups exist, who is in them, or what permissions are assigned to each user or group unless we are told. Therefore, failing detailed information, we can only give general instructions.