I too started seeing this issue recently, its not something related to Graphene os.
Apps started doing a check on the source of installation, if it finds the installation source is something other than play store it redirects to google play store or if the play store is not installed the apps just crashes.
try installing the apk through ADB using the command, this will make the app installation source as google play store.
adb shell pm install -i "com.android.vending" -r (path to apk)
first you need to push the apk to tmp folder using .
adb push app.apk /data/local/tmp/app.apk
adb shell pm install -i "com.android.vending" -r /data/local/tmp/app.apk
hope this works for you.