Phone Security Issue - Installing Apps From Unknown Apps Keeps Switching Back to Yes

[cf1425]

Hi,

I have an UMI Diamond phone (Android 6.0). I have the Malwarebytes app installed. And it occasionally notifies me there is a security issue with 'Installing apps from unknown sources'. So, I go to Settings, Security and switch 'Unknown sources - Allow installation of apps from unknown sources' to NO, and the problem is temporarily fixed. However, it keeps switching back to YES because when I open Malwarebytes a few days later I am again notified that there is a security risk with 'Installing apps from unknown sources'.

So, why does it keep switching back to YES, and how do I stop this from happening?

Thanks

 

[belodion]

Does it persist in Safe Mode?

Also, is there anything in Settings, Security, Device Administrators that might be causing it?