The left picture is what Transportman means
![connected.png](./download/file.php?id=187636)
- connected.png (158.1 KiB) Viewed 2042 times
You may see 2 possible platform destinations in your game behind each exit signal, but the signals don't take impossible corners into account, and see full crossings like I have drawn.
There is a second connection between different groups of tracks shown at the right. What we see as exit connection is just a valid train connection if you don't consider impossible corners.
If you take out both 'impossible' connections, the exit signal behaves as you'd expect:
![connected2.png](./download/file.php?id=187637)
- connected2.png (69.14 KiB) Viewed 2042 times
A simpler working layout is using path signals:
![connected3.png](./download/file.php?id=187638)
- connected3.png (340.61 KiB) Viewed 266 times
Being a retired OpenTTD developer does not mean I know what I am doing.