It's a good idea to keep all of your rubber seals treated with something like Wurth rubber treatment, glycerine, or another quality brand (not with silicone nor black dyes though).
Targa seals will be less pliable when dry & squeak - especially when cold &/or old, so treat them all. Look at what Curtis mentioned above on the latches too.
After treating the top's seals - plus the on-body/roll bar, windshield-frame, etc. seals mating to the top - all with the top off, allow it to sit & soak for an hour or so, then wipe off any excess, then try reseating your top unlatched to sit exactly in place at all 4 corners & along the 4 sides & square, then re-latch everything tight.
I used to do this every year or two in my garage, with the top on the floor upside down lying on an old towels or blanket, & I did the rest of the car's seals then too.
It's really hard to pin down one point for a squeak, & the seals need some care to stay pliable long term too, so this maintenance step is good overall, & you might as well do all of the other body, door, window, deck lids, etc. seals at the same time as one project.
Good Luck!
Tom
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