Over A decade ago I was lucky enough to be able to buy an All American les Paul Studio - unbeknown to me it had been fitted with a jap bridge.
Two years later, I had to spend almost a year in hospital.
During this time the 'B ' string had chewed another groove in the bridge - I had constant tuning problems as the ' B ' string moved between the two grooves during strumming - I couldn't see the extra groove, but I could feel it.
I filed away the ' Wrong groove ' and it cured the problem.