@durm, I concur that that’s the most probable reason:
I’ve had my fp5 for about a year now, and I’ve not had any connection faults yet, unlike my fp4’s, despite them appearing similarly poorly attached. I attribute this to only charging it with my battery pack in my side cargo pockets, rather than my diagonal standard trouser pockets, because it puts less pressure on the port.
I’ve always thought that not supporting USB-C’s screw threads was a strange decision, considering that FP is hopefully immune from most manufacturer’s desire to sell accessories. [1]