Import problem with capella file after safe-and-reopen file

I have a curious problem with the appended capella file:
the initial import seems to work fine, everything looks ok. But when I save the file as mscz and reopen it, I get a lot of errors. Mainly it seems that the file is saved as 4/4 although it's 3/4.
Additional hint: the mal-imported header must be deleted (twice) before saving, otherwise MuseScore cannot open the file at all.