T2 wagon unloading in mixed station corrupts train state

Issue description

Unloading T2 wagons in a staggered mixed cargo station (eg rock-slag-rock-slag station buildings) causes the train to become corrupted.

Train is stuck in "unloading" state, no more unloading happens even though there is space for it, and the train doesn't report any problem, just stays there forever.
See attached image, observe even the cargo graphic is corrupted, with horizontal half of it missing, instead of the wagon being half-empty vertically like normally mid-unload.

Reproduction steps

1. Load attached save
2. Observe corrupted train (only train on map)

Game version and build number

v.0.8.3a b578

Operating system

Windows

Attachments

T2TrainStuckUnloading.save

Actually, works as intended, the crucial missing info on my part was that the magic connection between stations only works with stations of the same kind directly next to each other.

I also didn't realize that the T2 wagons ARE designed such that we can have them half-n-half filled, which resulted in the above graphic.