The stroke is showing through the fill on the same layer
When I make two shapes on the same layer, I put the brown one above the grey one, but sometimes when this happens, the stroke of the grey shape shows through the fill of the brown shape. The transparency of the brown one is 100% and I try to send the grey one to the back, nothing happens.
(when I delete both shapes and the layer and start over, it fixes it, but I want to know why this happens so I don't get too far in my project and have to delete everything.)

