I don't know if we can call it bug but by creating a view of the character using "Flip Sprite" FaceDirection not working properly.
It's necessary to use existing sprites for each loop and FaceDirection will be fine.
[edit]
To be precise behavior is strange.
I had the loop Left, Left-Up and Left-Down mirrored.
Asking AGS perform FaceDirection(eDirectionUpRight) (this loop was not mirrored) was displayed eDirectionDownRight...
So I proceeded to mirror all frames manually and import them directly as sprite and assign them to the corresponding loop.
Now all directions work properly.
It's necessary to use existing sprites for each loop and FaceDirection will be fine.
[edit]
To be precise behavior is strange.
I had the loop Left, Left-Up and Left-Down mirrored.
Asking AGS perform FaceDirection(eDirectionUpRight) (this loop was not mirrored) was displayed eDirectionDownRight...
So I proceeded to mirror all frames manually and import them directly as sprite and assign them to the corresponding loop.
Now all directions work properly.