Comment 4 for bug 938302

Yes, this is a known quirk. Onboard in Ubuntu is set up to enable screen saver integration by default. This happens on first start and has to be turned off manually in preferences.

We just recently talked about this again. What we could do from Onboard's side is to refuse to start in g-s-s when either Onboard wasn't already running in the user session or the on-screen keyboard is turned off in accessibility settings.

I'm not sure yet if this isn't something that should be solved outside of Onboard though. perhaps by disabling/enabling the relevant g-s-s gsettings keys when toggling the osk in accessibility settings.