Can't zip mail files in Maildir Dovecot

Problem with Dovecot Maildir.
The button “Download folders in zip archive” does not work in the web interface if the folder containing mail files, for example:,S=1229,W=1255:2,
In urbackup.log:

2020-01-24 15:04:19: ERROR: Error while adding file “/backup/urbackup/,S=1229,W=1255:2,” to ZIP file. Error: invalid filename. OS error: Code 0

If the mail file does not occur with a similar name, everything works.
I suspect that when archiving file names are incorrectly escaped, but where to fix this is not clear
I use FreeBSD 12.1 and UrbackupServer 2.4.11

Yeah, it is an issue with :. The zip spec says it’s not allowed in zip files. This is “fixed” (check removed) in a never version of the zip library. Will update that…

Thanks for the answer. I will wait