Import from 3.6.2 to 4.1 messes up voices and ties
voice 1 and 2 were swapped
Ties in voice 1 became slurs from the erstwhile voice 2 to voice 1
It also seems that I cannot manually redo the correct ties as 4.2 seems to insist on slurring from the new voice 1 to voice 2.
Look at the uploaded 3.6.2 example and see what happens when it's imported to 4.1