It takes a lot more force than most people think to punch or tear a hole in 45 mil EPDM. It could be that the seaming that you did is losing its integrity. This is a common problem if utmost attention is not paid to surface preparation prior to seaming and applying the proper amount of pressure to the seamed area after seaming. If a seam's integrity is questionable, it only takes the slightest lateral stress to lose adhesion.
There is only one sure way to remedy this problem and you already know what that is.
Sorry, my friend.
"Everybody is ignorant, only on different subjects." - Will Rogers