Sidebag lock barrel install snafu

[BeemerBobby]

Installing the lock barrels into new BMW side bags today. Matched up the locking tabs/pins  inside the cylinder. They were all flat when key was inserted. As per instructions.
My problem began when I put the last metal tab into the barrel--the "stop" one.
All looked good. Slid the barrel into the side bag and turned it to it seated correctly. Worked great. Bag locked and unlocked smoothly. BUT I CANT GET THE KEY OUT OF THE BAG!! WTF!

Anyone have a clue?