In the picture below, I expected the chain signal allowing NW travel to be blue since only one of the two possible exits to the block has a train in the block but it's showing up as red.
In the picture below, I removed the opposite SE signal and the NW chain signal is behaving as expected (blue).
In the picture below, I shifted both chain signals one tile to the southeast added back the opposite SE signal and the NW chain signal is behaving as expected (blue).
In the last one below, I removed all the straight diagonal rail, placed the curved rail, placed the chain signal, and then added the diagonal rail. The chain signal is showing up as green but the expected behavior is blue.
This tells me that the chain signals, while being shown as spanning the merge point between the curved rail and diagonal straight rail (yellow block arrows), one rail instead of both at the merge point. Either signaling the rail that it was first attached to, or it is only signaling the rail to which is closest to it. I have not tested this with normal rail signals do not know if normal rail signals also exhibit this behavior
Seems similar to the following two bugs but wanted to let you know in case it wasn't:
viewtopic.php?f=47&t=17757
viewtopic.php?f=41&t=14347
