Oddly enough, we had exactly that problem with mecanum wheels this year. They were all labeled properly, but somehow someone had managed to switch them around. It was a frustrating programming switcharoo obnoxious time trying to debug the code and figure out why nothing was quite working right and then it was 'oh, change those out' and everything worked fine.
Remember how this works:
Mechanical blames electrical.
Electrical blames programming.
Programming blames mechanical.
