player getting stuck

Guys,

What could be causing a player to get stuck on a landscape map.

It happens when the player is close to/touching a hillside but the area directly in front of them is flat or seemingly so to walk on?

There are small bumps in the terrain, I’ve tried many times to smooth the hillside and terrain but no luck, the area looks pretty much flat to the eye, each time the player gets to a certain point they just become stuck, whereas the vast majority of the map is fine?

The walkableFloorz is set to 0.85.

Any ideas?