In/out play in coupler

Here's one without. Not sure of the application............
upload_2021-1-29_11-11-55.png

Not that it's the solution to your telescope issue, but a pin would probably help deter your shoes from wearing on the seal and coming out of the cup if the cover fails.

Maybe some useful info on couplers here.........
Mopar Steering Column Coupler Info - Detroit Muscle Technologies, LLC