I've managed to recreate this by changing my Keyboard to French. I'm not sure where the weirdness comes in. British works, German works, but French has a definite barcode accent which might be shared by all AZERTY keyboards!
If your OS has an option to change the map for only the barcode scanner (I doubt you want your normal keyboard to be anything other than AZERTY :-), that should fix it. I'll see if I can find a code for changing the way the barcode scanner works as a 'proper' solution.