I wouldn’t worry about it too much; bm’s should change throughout your treatment from good to bad and back and forth…atleast this is my experience with it despite eating the same thing everyday.
The diarrhea is slightly concerning and could be associated with the kefir. You could move to goat’s milk kefir if it becomes a problem. Did you eat anything not allowed on the diet…was the food old?
I wish I was more helpful, but as long as you don’t get other candida symptoms and just BM issues…this isn’t worth worrying about too much. If you get unusual bm’s with skin breaking out and acne (or other symptoms)…that should be a concern.