Thank you very much David for this quick return.
The start of my project is at -7,1,1. I leave room for a pre-intro.
I have just tried to remove the pre-intro and export the midi again, indeed it works well this time.
Do you know why? So the start marker should always be at 1,1,1?
(I specify that in spite of the pre-intro, my region with the midi started on 1,1,1)
Have a nice day,
Arthur