Could this be spider mites or some other critters??

I don't think this is a sign of mites or insect infestation, it's more likely a genetic variation, but it could also be heat stress or a watering issue. I wouldn't give it too much importance, it'll outgrow it. :)

Spidermites, nooo, are far too easy to spot and rapidly multiply/infest. The only thing I see is slightly raised up margin edges, which are normally associated with a very slight water issue. The plant is losing a little more water than it is able to bring up through the roots; turgor pressure is unable to "inflate" the entirety of the leave/tips" and/or lacks the necessary water to keep them(leaves) supplied with enough water to keep up with the cooling demands of photosynthesis. Honestly, it's a very small problem not worth worrying about; possibly slightly over-saturated soil. Those fabric pots are not as airy as you may think; if RH sits over 50-55% regularly day/night, I could see it slowing things down. She looks healthy and well grown; not to worry yet. Turgor looks solid.