Okay this will sound weird I went to Samsung store and tested another cover and nothing changed so I went ahead and tested with another device in display And I found out that the S8 and S8plus does note lock screen when you close the cover like the case with the note 8
that's very weird from Samsung and compromise the security of the devise cause if you close the cover, the device will not lock till the screen timeouts which the min for it us 15 sec
