mate-screensaver switching theme to "Blank screen" from "Picture folder"

[highflux7]

After successfully displaying images from the "Picture folder" for several hours, mate-screensaver v1.24.0 on my Ubuntu Mate 20.04.2 box(es) seem to forget about the Picture folder theme and switches to the "Blank screen" theme instead.

So far, I've only been able to kludge around this by periodically killing mate-screensaver and restarting via a cron job:
i.e. export DISPLAY=:0 XDG_RUNTIME_DIR="/run/user/1000" && /usr/bin/mate-screensaver-command --exit && mate-screensaver & disown