Problems with 5.1.1 V2.6

[GottaGetX]

Azoz- Make sure "Don't keep activities" is not selected AND turn the app on in "Protected apps"

Gaw - turn on hide navigation key option in display settings.

I have already done these. Still no luck ):

Don't keep activities should be unchecked by default. There's nothing you should have to do with that setting.

You can try to convert Snapchat to a system app. Or see if in Snapchat there are any settings for "keep in memory". If none of those work, maybe try 5.1.1 with Google and multilingual.