1. Maybe because they are being pushed into the Anagen phase( growth phase) for a longer period.
2. Derma rolling didn’t stop the post minoxidil shedding in my case
I can understand your situation as i got caught in the same scenario as well, for now i suggest you to lower the dosage to 0.15mg thrice a week and see what happens If side effects still persist then completely avoid and go for other alternatives like hair supplements + saw palmetto(300-600mg/day)
It is probably androgenic aloepecia which is the case among 90% of hair loss sufferers, you should start with finasteride for atleast 6 months along with keeping track of the progress made