Hi Aviel! The color of the leaves is on the lighter side. How often do you feed your trees and when did you pot up the tree? From my experience, those kinds of leaf burns happen when the plant is overfed or is root bound. Doesn't look like overfed. After fertilizing don't let the tree dry, keep it consistently moist, not soggy.

Salt??? Do you perhaps water your tree with water from a water softener?

Salt burn/buildup can also result from poor drainage.

I would doubt any disease; Kaffir/Makrut limes are probably the most resistant on the planet

i don't think it is rood bound, i actually repoted it maybe 2 months ago and added compost to the mixture. to be honest, i am not feeding it by the book, just adding some compost.

John is correct. Also, it may be due to something that was sprayed on it.

Try flushing it out really well at your next watering, it should help wash out any salt build up. Use quite a bit of water letting it run through the holes on the bottom. If that is a 1 gallon pot flush 3-4 gallons of water through it. The compost may not be the best thing to use in a container. It looks like your tree isn't getting enough nutrients by the color of the leaves, they should be a pretty deep green.