Initial setup:
![Image](https://forums.factorio.com/images/ext/5bef3a74158c77677790b1294c1bd28b.jpg)
Train goes to station on right, stops before the lead locomotive completely passes the signal:
![Image](https://forums.factorio.com/images/ext/32feab84d745269b140f20169171bdc1.jpg)
Train leaves for station on left, signal at bottom right stays yellow:
![Image](https://forums.factorio.com/images/ext/448f5a61a7576ee17ad275065dd87842.jpg)
The presence or absence of any other signals before or after the stuck one makes no difference that I can find.