Glock drum misassembled - ProMag Glock 21/30 .45 ACP 40 Round Pistol Magazine

Have bought this exact drum before with no problems in functionality. This one was assembled wrong from factory. Follower tab was trapped inside the rectangular mag and not the drum. Not allowing rounds to be loaded. Factory quality inspection could not have been done otherwise problem would have been caught while trying to load the first round. Disassembled, repaired, reassembled, tested (myself). Product works fine now.