Text line missing when saving in Musescore 3

Hello,
I'm trying to transcribe this Mahler in braille, but before doing this, I found a strange problem. The 5th movement is here:
https://musescore.com/user/2675376/scores/4856193
The problem is, there's a text line "poco a poco cresc. al", which is not only unable to be exported into Musicxml, but also lost when saving in Musescore 3! The musicxml export should be a and a bracket or dashed line (musicxml has no ability to spread words along a line). But why it gets lost in Musescore 3? I think we should carefully sum up issues in MS 3.

Haipeng