Opening the Dynalist backup files results in "Illegal byte sequence"

Steps to reproduce

Unzip a Dynalist backup (after Dec 26 2018) file, either the txt or opml version.

Expected result

The zip file should get unzipped.

Actual result

I get the error message "Unable to expand “dynalist-backup-X.zip” (Error 92 - Illegal byte sequence)

Environment

Mac OS X High Sierra.
I’m using both Desktop version and mobile app.
Dynalist 1.1.15


Additional information


Additional comments

This only happens for backups later than Dec 26, 2018. I don’t know how what I added/changed on this date.
Using the unzip tool on the command line also does not work - it gives me lots of “checkdir error: cannot create ???
Illegal byte sequence”