Possible bug: Signal closing and yellow signal

[Aeternus]

Short version: Closing a train signal by circuit has no effect if the signal is yellow.

Another possible bug, possible working-as-intended pertaining signals. Consider the following situation:
Trains exit a stacker to a waypoint station. There is a circuit controlled signal that closes if the unloading stations behind the waypoint station are all occupied, meant to block the train before it can get to the waypoint. (To prevent trains from trying to get to a station that is not able to receive its cargo).
I've noticed unexpected behaviour with the signal closing. If a train exiting the stacker reserves the block leading to the waypoint station (the circuit controlled signal turning yellow), closing the signal by circuit does -not- turn it red and stop the train. It will turn and stay red only when the train passes it.

I've worked around this by placing a second not controlled signal right in front of it, which makes the system works as intended. The uncontrolled signal takes the yellow, allowing the signal behind it to be circuit controlled.

[SpaceCat-Chan]

This is not a bug because if the signal is yellow that means the train is unable to stop before already crossing the signal thus making the train be past the signal and then continuing on anyways. that is why you can't change the signal.

[Twinsen]

This is not a bug because if the signal is yellow that means the train is unable to stop before already crossing the signal thus making the train be past the signal and then continuing on anyways. that is why you can't change the signal.

Exactly that. The behavior is also mentioned in the tooltip.