We have seen this many times when the windward boat has room at the mark when an overlapped was established before the leading boat entered the two boat length zone. That is ok provided that when the inside boat established the overlap the outside is able to give room, see rule 18.2.a.

If the outside leading boat can't give room when the overlap was first established, the inside boat is not entitled to it, see rule 18.2.a. If another outside boat is in the way, or the boats are sailing at high speed and hard to control, or the boats are drift sailing, it is hard to do the impossible.

This does not mean every occurrence for room at the mark, only the times where giving room is impossible. Many times a group of boats are trying to round a mark at the same time and the inside overlapped boat asks for room, but it can't be done. The closest outside boat just can't give it. When this happens, the inside boat is not entitled to it.

Once again it is best to read and know the rules to keep you out of trouble.