Yeah, this is a known issue with these antenna on Amazon, this seller even has a pic in their gallery to show you how to spot the fakes.
https://smile.amazon.com/gp/product/B07TC5WTYL/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Unfortunately, the only way to avoid counterfeits is to buy them from a reputable shop and not Amazon. Because of their binning system you really can't trust much of anything from Amazon these days regardless of the seller. If someone makes a counterfeit version of something it's pretty much guaranteed to be mixed in with the real stuff in their warehouses. This is especially true for generisized knock-off products like those antennas that get rebranded by 10 different sellers.
These fit like factory:
https://www.amazon.com/ABBREE-Foldable-SMA-Female-Connector-Waterproof/dp/B07TC5WTYL
Idk if it's specifically is waterproof or keeps the radio waterproof, but the Abree tactical comes with a rubber grommet and fits flush nicely on an UV-9R
https://www.amazon.com/ABBREE-Foldable-SMA-Female-Connector-Waterproof/dp/B07TC5WTYL