devtrackers.gg
Most of the signs can display a black background if you chose "nothing" with arrows on top.
Some just can't, in a very non consistent way. For instance in my track I had to accept this (the right one is the problem) and it did the same for the smallest rectangle signs :
Some just can't, in a very non consistent way. For instance in my track I had to accept this (the right one is the problem) and it did the same for the smallest rectangle signs :