I had that problem on my VX-7R when i had it, some antennas would work and some didn't have a long enough center pin for the connector, so you always have to be mindful of that!
Thankfully on the FT-60R i haven't experienced that problem yet. I took my Nagoya cheap chinese antenna, basically a Diamond knock off, and put it on my T100 Vector Antenna Impedance Analyzer and it looks great from 144-155, and 440-460, beyond that and the SWR climbs over 2:1.
The trick to remember when checking one of these HT antenna's is if your analyzer doesn't present enough of a ground plan then add a counterpoise to it for each band as the HT's metal frame is the counterpoise when in use. I had to take a ring terminal and washer and make a counterpoise for my analyzer to check them on it.