MIDI export doesn't contain all the parts

Hello,
I made a fresh score with several parts (orchestral string section) (score not_working in attachment). When I try to export to MIDI only violins 1 are exported, the other files appear empty (i.e. empty score on musescore, no events when opening with Logic Pro either).
I was wondering if it comes from my computer, so I made another score inputted a few notes, exported it to MIDI and no problem occurred.
I'm thinking that some of the markings (lines? dynamics?) in the first score are causing a problem during export. I attached both test files to this report. I'm using Musescore 3.6.2 on a MacBook Air (Retina, 13-inch, 2018) with MacOS 12.3.
Hope it helps. Cheers, and thanks for the great software 😁