As far as I have read this is solved by this patch:
https://github.com/frescobaldi/frescobaldi/pull/1401/files
which is simply adding int(...) twice. As python is an interpreted
language
you can apply this patch to an existing Frescobaldi installation.
So you simply have to open this file on your local Frescobaldi
installation
(which should be a path like
/usr/share/frescobaldi/frescobaldi_app/widgets/
progressbar.py) with root access, go to the affected lines (74,75)
and add
these int(...) parts.