In version 12344, "Private Road" signs cannot be placed on diagonal roads. All other signs work.
That is not new; it has from the beginning been that way.
Exactly ever since this sign/signal was changed from the standard graphics to the "open/closed" version.
An "either/or" approach would have been better.
The sign needs to state to indicate a player whether it could use. With the graphics then, it was only four directions and looked silly for diagonals.