OT crossfader rubber cover comes off easily

Does the rubber cover on the OT suppose to lift off easily? I just bought an OT recently and the rubber cover seems to simply lift exposing the metal cross fader knob/thingy.

My OT is almost three years old and it has never seemed the least bit loose, and certainly never come off.

I imagine you could easily fix this with a dab of rubber cement, or even putty or chewing gum lol.