Implode from multiple voices to one voice doesn't copy note velocity and tuning
1) Create score with multiple voices
2) Change note velocity and/or tuning in one voice
4) All the note has 0 offset velocity and 0 tuning
BTW, imploding multiple staves to single staff, multiple voices does copy note velocity and tuning.
OS: macOS Mojave (10.14), Arch.: x86_64, MuseScore version (64-bit): 18.104.22.16825, revision: e26f7c4