Sometimes the coach is designed to use one type of fitting like a long radius elbow and for some reason start installing a short radius elbow causing your problem. Two possible solutions:
If it really is a long vs short radius elbow problem replace the short radius one with long. If not remove that ring on the bottom and position it a few inches forward. Should be able to do that with no glassing but if not the dealer will have to glass in the aft edge of the hole.
David
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