Probably because he does not have mites is why they are recovering. Just because a plant has some issues doesn't mean mites, there are many many reasons plants have issues. It could be competing roots with the triple planted pots. It could be heat stress, over watering, mechanical damage, micro nutrient issue, tainted water source, water on the leaves in afternoon sun, etc. Schrews plants look healthy and healthy plants do not acquire pest issues outdoors easily.
Vibes
+1000000 VERY WELL SAID