Odd Litter Box Behavior

So our 5 year old Himalayan (female) likes to walk through her litter box once/twice a day. I suppose this does not indicate anything wrong, but once in a while (2~3 times a week) she will dig and crouch as though she's about to pee but then gets up and out of the litter box.

It's a tad odd, because she just sits there without showing any signs of straining to pee.

Luckily her check-up is this week, but I was curious if anyone else has experienced anything similar.

Cheers.

It would probably be a good idea to let the vet know about this. I suppose it could be indicative of a UTI in early stages. Feeling the urge to go, but not being able to?
Hope it's nothing, but always better to check and be sure.