Ah, so you need to set the platform to “Static”. You can use the arrow next to “Collision Presets” to customize what each collision reaction is. Your pawn should be set to “Pawn” and your platform “static.”
Now as far as detection goes, you don’t have any form of detection coded. It’s just getting two locations, and moving, the way it’s coded. If you want to be unseen, you might consider adding a “Line Trace By Channel” and drawing a line between the player and this pawn, then only executing movement if the trace is blocked first by the player and nothing else.
The Navmesh has nothing to do with detection, it’s only supposed to show AI where they can move.