Musicxml Export - Trill-type Drum rolls not exported

Hello,
Today I find another problem with the Musicxml export, both in Musescore 2 and 3. Please see timpani part of bar 46 or 47 in this score:
https://musescore.com/user/788211/scores/4861957
There's a trill if I go to the uncompressed Musescore file, but only the fermata is exported in Musicxml. If I am not familiar with the notation convention, I'll never know there must have a trill, and the braille transcription will be misleading if I post it to my project site, harming other blind musicians. Can this be added in the future version? Thank you!

Regards
Haipeng