Player sticking on stair steps

I have the same problem, I have a kerb, 20 high and 20 deep that the character in game (using the FPS template) refuses to walk up.

Here is a shot in Maya of the dimensions

If I change the walkable floor angle to 90 degrees in the character Blueprint it works fine. I’ve tried extending the depth of the kerb to 30 and its still the same. I would like to keep the default settings on the character if at all possible.

The strange thing is, I can walk up a height of 40 units, but not up 20 (as shown below)

Its driving me insane, so any help is appreciated.

Grant