Issue editing a slur across a page break (expression slur, not tie)

Hi everyone,

I’m encountering a recurring issue with slurs in MuseScore (using an expression slur, not a tie).

In measure 27 of the score attached (7/4 bar), I need to insert a slur that crosses the barline into measure 28. The slur is correctly created when I select the full range of notes, starting from bar 27. However, once it’s applied, I’m unable to adjust its length or shape — it simply doesn’t respond to any editing. Strangely, the part of the slur in measure 28 can be edited without any problem.

Automatic placement is turned off, so that shouldn’t be the cause. Also, there's a page break at measure 20, in case that has something to do with the issue.

Has anyone experienced this behavior before? Any suggestions or known workarounds?

I've attached a screenshot and the .mscz file for reference.

Thanks in advance for your help!