It appears that when we try to set a non-existent key in a gsettings schema using the GSettingsHandler, an error occurs and the code core dumps. Here's a log:
(process:2329): GLib-GIO-ERROR **: Settings schema 'org.gnome.desktop.a11y.keyboard' does not contain a key named 'screen-keyboard-enabled'
./start.sh: line 19: 2329 Trace/breakpoint trap (core dumped) node "$fileName"
I haven't yet reproduced this issue consistently with a particular persona, so it's possible it was just some kind of weird bug or quirk.