Q.Deteriation Of An African Violet. What Causes This?
I have tried transplanting. I’ve tried removing the roots to reboot. I’ve had perfectly healthy violets loose their leaves till they look like the picture. I’ve grown violets for many years but can’t figure this out.

Certified GKH Gardening Expert
It's probably overwatering or soil that isn't draining well. Are there holes in the bottoms of those cups? They are picky about watering. Using distilled or bottled water may help. Also, make sure the leaves don't get wet when watering.
https://www.gardeningknowhow.com/houseplants/african-violet/african-violet-care.htm