Automatic update checking pref broken

I’ve set fotomagico 3.8.7 to never check for updates. It tries anyhow. So I tried setting the SUEnableAutomaticChecks key in com.boinx.fotomagico.plist to “false”. When I start fotomagico the key changes back to true! I even tried changing time of last SU check a year ahead. Doesn’t make a difference – fotomagico checks anyhow. Looks like a bug to me?