I don't think there was something wrong with the armor, but with the painting process it had. Just to explain to you that (by the way, no names are supposed to be showing from suppliers in this forum, use abbreviations i.e. RA).
Somewhere in between there was an important step that was left over, or wasn't correctly done. Let's say...light sanding the armor first to apply the coat of primer before masking and painting (all in that order). Just a wild guess.
Besides, the kind of paint used probably was too much for the effect, which you was supposed to paint it in light coats first (main word here is PATIENCE!), probably 2-3 coats of the main color will be enough. This were just my 2 cents.
Other than that....keep them away from heated or hot surfaces or direct sunlight.
Robert