I looked up this issue but couldn't find it so I'm posting the fix.
I'd been having a very annoying issue with only a couple of apps (from the same vendor) installed through the Google Play Store where when I opened these apps the screen switched to a Google Play screen that read:
"Close apps to continue
To continue using [name of the app] close the following apps. These apps could be used to view or access your information in [name of the app].
Apps you need to close" And then Lawnchair and a screenshot tile app. (I have a screenshot of this screen but I guess you cant post images here)
I guess these two apps used a security check through google against apps with a lot of permissions like Lawnchair, which is a homescreen app. Other apps installed through google play don't do this, including banking apps.
First of all, you dont actually have to close the apps it says. Just ignore the "close apps" button and the close button up top. You can just hit "back" in the android system buttons, and you can go back to the your app. But it's annoying doing it every time.
To stop it I went to androids settings/Apps/See all apps/Google Play Services
In the Advanced section I disabled "Picture-in-picture", I think. I have everything in this section disabled now.
I assume that's disabled by default in the Graphene play services version, but that I had to enable it to log in for some banking app.
The "Close apps to continue" screen is not showing up anymore, and nothing seems broken.