If I go into analysis mode and select the triangle, then go back to the game, this is what the stone shadow (“where the stone would go if you click”) looks like: 
Aaand… Probably I should just see the stone, not the triangle. 
If I go into analysis mode and select the triangle, then go back to the game, this is what the stone shadow (“where the stone would go if you click”) looks like: 
Aaand… Probably I should just see the stone, not the triangle. 
Can confirm that this happens with the shape markers, but not so much the letters/numbers although I don’t want to check them all 