Default [Q] apps uninstalling themselves??

Happened abpot 4 days ago with gasbuddy... and then today with rom manager... what is happening???? The only new app I have installed is greenify... is this a problem?

Neither of them I used a lot but I'm not understanding what happened. Rom manager I never even stopped fromm running manually within settings. I had done that with the gasbuddy app.

How can I ensure this won't happen with anything else? I would HATE to lose game progress due to this.... bug or whatever it is!!