Description of the Bug
When placing a signal adjacent to a metal post, the post develops "arms"; connections to the signal, but matching connections do not appear on the signal. This results in an air gap between the signal and the post where there shouldn't be one.

Expected behavior
The signal should get matching arms to complete the connection to the post visually.

Screenshot

Railcraft 12.0.0 on Minecraft 1.12.2 - I remember this working correctly in a previous version of Railcraft+Minecraft, but I can't remember which one.