Here’s a lot more clear example of this bug.
When Theudobald – archer on the lower ground in the middle, using short bow (cursor is on him) – tries to shoot someone, the range / vision grid shows some kind of obstacles, while clearly there is none.
using 1st skill – Quick shot
using 2nd skill – Aimed shot
And if you look carefully, the grid shows he can even shoot a spot behind the bush on the hill directly north of him, which is wrong.
He’s the first one to make a move after battle began, nobody moved or used skills yet, if that changes anything..
After waiting turn and then using skills the grid shows proper results:
Here is how it looks for Robert, who stands beside him on adjacent tile: