N5-X25 to C5x threads

We got a batch of N5-X25s that won’t screw onto a C5x. Can’t even get 1 full rotation. It is NOT the set screw, doesn’t get that far. Tried 3 dishes with 2 different C5x’s. A 20 dBi dish works fine. Picture of 20 and 25dB antenna threads next to each other shows the difference.

I would go directly to Mimosa Support with this issue.