I think you need to establish some "tooth' to the painted surface.
Suggestion #1 Mask and use a narrow Dremel 3m scotchbrite wheel and abrade the exposed painted surface. Remask and refinish.
Suggestion #2 Could be the angle you re "pulling" on the masking, It need to be pulled at 180 degrees, dont pull "UP" lifting paint.
Suggestion #3 Timing, more cure time required before masking removal.
Hope this is helpful
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69 Los Z11
68 SS/RS 396/325
68 Los Z28
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