That's normal. Mine was like that also when I pulled mine apart to examine for problems related to the same issue you're having. I was having some ghost triggering along with a lot of double triggers. I've gotten mine calmed down mostly, but I've still noticed some on occasion. I put a patch on the head and switched to the felt side of my beaters.
I've noticed that if I hit lighter, I have the problem a lot more. You could try loosening the head, but I don't think it has quite as much of an effect as the other pads because of the big foam column. That was my observation anyway.
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Shawm