I have to assume the center receptacle is not forward enough (ruling out the name N connectors)
Before you give up are you sure your N male on the feed line is not the problem? N, BNC, and TNC are very sensitive to cable strip dimensions with very tight tolerances especially with respect to the center pin. On the commercial side we use a feller gauge to inspect the center pin placement. +0 / -1 mm tolerance. The center pin ideally should be flush with the Outer Contact Sleve, and no further than - 1 mm.
So before you give up check the center pin forward placement. If you find the point flattened, it was too long and possible pushed the female contact back on the antenna. You might get lucky and just find the feed line connector improperly terminated and an easy fix.
I'm going to have to check the model number of that antenna, either it's the wrong model number I posted, or it's the wrong antenna. It's suppose to be the 'commercial' version of the 2m/70cm version that many other companies offer.
I find it hard to believe two N male connectors, both were bad. I substituted a 'discone' for the time being and I see no similar behavior.
What was happening was a fluctuation in the RLB scan of the antenna. I could loosen, then tighten (by hand) the connector and the pattern would change somewhat.
I did pay special attention to both center pins, the males were not damaged, the points were not flattened.