Moving a neume component moves others often

[MrMondrian]

out.mp4

buggy.zip

Sometimes a bunch of neumes get shifted and moving a nearby neume component causes them to shift. I've upload relevant files for testing. Recently there were changes to the MEI encoding job that I thought might be related, however after E2E-ing with and without the changes, the results were the same.

[yinanazhou]

Probably because the clef in the staff is not recognized. We can try to assign a default C to the staff and see if it helps.