@frlan I downloaded the PPA package and noticed that this **still** happens to be the case. I rebuilt the git-changebar plugin from source and just swapped out the .so file from the .deb file.
Download: https://github.com/gsantner-extra/gs-debian/releases/download/upload/geany-p...
I built from commit https://github.com/geany/geany-plugins/tree/9694c624d6a3ff579dc03f84f24f4c99295f0027 and running it fine on Ubuntu 18.04 + Geany 1.34.1 (from PPA)