I think they might have different firmware because the right one has an IR sensor. So since the features aren't the same, the software might be slightly different.
iirc that was a design defect and not a manufacturing defect. The material of part of the design warped over time due to poor heat management iirc.
Negative, both joycons have this issue....
See here https://www.youtube.com/shared?ci=sXSqmsCL9a0