It shouldn't send any screenshot notifications out of itself.
Snaps and stories are saved automatically, you don't have to do anything (so don't take screenshots yourself if you did that).
You can send me your Xposed log if it happens again but I doubt there will be any useful information.
I can't seem to reproduce the notification, even when developing and breaking Snapchat a few times I still haven't gotten any notifications.
Do you have any other Snapchat Xposed modules installed? Try disabling those and see if it is fixed.
actually i've no screen cap notification, and no notification on the friend's side.
i forgot to say that i applied the wipe in the folder "/data/user/0/com.snapchat.android/files/media_cache"
and let snapchat resynch the stories after reboot.
so for me it's all good