Pathfinding problem on custom bridge heads

[DaleStan]

When loading the attached save, you are looking at train 132 enter a depot for servicing, prior to making its way to the SE towards its next station.
While it is pulling out of the depot, train 134 (which shares orders with 132, and should follow the exact same path) comes careening over the bridge, realizes its desired path is blocked, and heads off to the SW instead.

Observed in TTDPatch a67, a60, and a55

stuff.rar contains the usual; save and both cfg files.

[Patchman]

To save me some time, can you determine whether it's really the bridgehead that's causing the trouble? Just temporarily replace the bridge with regular track (of course you'll have to remove the tracks below), to see if it's a general pathfinding issue or really specific to bridgeheads.

[DaleStan]

I have similar constructs elsewhere on the map, so I assumed..., but we all know what they say about assuming, right? Anyway, it came true.

It happens even if there isn't a bridge there.

Savegame, with normal track, from just before Train 132 reserves its path into the block. Same newgrfw and ttdpatch.