count me in on this phenomena as well. My take is that it is evidence that our systems are still in need of healing through fasting.
I've fasted over 100 days over the past year. Many, many issues were resolved. Many that I didn't even know I had. But this problem still persists.
I know I need more fasting because, although I am much better than I was before fasting, I still have antibodies indicating toxins that have yet to be removed.