After a few copy-paste of slurs from one measure, suddenly a new slur is created from the beginning to the end of the score

And when I write that a new slur is created, this is obviously the very first result. By continuing eg two copies, you get a bunch of slurs, from the beginning to the end of the score, impossible to count (except of course by going to see in a text editor)

And as said, all these slurs "lines" are no longer visible (quite impressive!) after save/close/reload

• Eg, a result in a part:

After save/close/reload

And for the sound loop, it is not so difficult to reproduce. Eg this file: two notes.mscz
Click on the A, the problem appears. And by clicking again on the score (one time or two), the problem becomes much more serious ...
So, I guess a bunch of slurs attached to this particular note is at the origin of this behavior.

I observe a change in August 2014 (just before the Beta1) with slightly different and reduced steps:
1) New score
2) First measure : enter two half notes with a slur
3) Create parts → new all → Ok
4) Copy first measure main score -> Paste in part first measure
5) Return in main score, and repeat the same previous copy-paste three other times
(so a total of four copy-paste from the main score to the part)

With this nightly, on August 22, 2014 ( 3d172d7) and some previous ones in August 2014, the slur is erased in the main score after its first copy in the part. So:

With the next one (f2ea47b), we can observe the current behavior, ie a new slur along the score (but we must make 5 copies instead of 4 actually with the 2.1, don’t know why)

• And so the subject was these issues : #29511: Voltas (and other lines) disappear upon entering notes and #28761: Lengthening note before a line produces incorrect results
  Fixed in f2ea47b
  and see also: https://github.com/musescore/MuseScore/commit/24facb5918b87c0cc8878b3b4…