Gear shaft plastic accordion style cover seems offline. Can it be fixed?

It will have to be replaced, shop around for a replacement and you have an Infiniti, what do you expect to pay, should have gotten a Toyota.

if I recall correctly, you can take it apart, clean it and put it back together, the sliding part fits in a rail and it's usually because the rail that the accordion style cover rides in is gummed up and causes the cover to jam and bind.

Spray it good with WD-40 and work it back & forth, spray it again!