Slurs settings and saving added instruments lead to crash

OS: Windows 10 (10.0), Arch.: x86_64, MuseScore version (64-bit): 3.0.0.4839, revision: cf1f5ce

Steps from scratch (the test file: test drum scratch.mscz )

• First scenario:

1) New score for flute, and drumset (instrument with Percussion clef or TAB clef needed here)
2) Enter two notes with slur in flute staff
3) In Inspector, change an offset (X/Y) or two, as you want
3) Press « I » → Add a new flute → Ok
First result : you note the slur reverts to its default position
5) Save (Ctrl + S)

---→ Crash

Note: if you want create your own test file, it's needed to save/exit/reload first the file (with custom settings). Then following steps with addition of instruments.

• Second scenario. Involving Auto Save feature, with the same test file.

1) Be sure 'Auto Save' is checked in Preferences, and set to 1mm, preferably for you and to reproduce.
2) Load the same file: test drum scratch.mscz, or another one, with Ukulele TAB: test TAB uke.mscz
3) « I » → Add a flute → Ok
4) Wait…
Result: here, with my laptop Win10, after 35-40 seconds, the program shuts down.

With my desktop computer Win7 (more powerful, memory involved too ?), sometimes it may die rather quickly too.
But the more often, after 50 seconds (the time for Auto Save, sufficient), possible that nothing happens. So, I repeat step#3, and there, the program dies, and not all the times, after 1.40-1.50mn

See (first scenario)