Noticed this long ago but still seems a problem in the latest on git: Create two, two-tile long dock canal stations, and a boat-horse plus a barge to serve them. In the boat's schedule, set the stop-tiles to be the ones closest to each other -- when you operate the boat, it will stop with the barge hanging off the end of the dock -- whereas it should work "like a train" and pull forward. In many cases this results in goods refusing to load, or unload, and barges endlessly hauling the same cargo (or empty barges) around the map.
Hmm, this is interesting, as I do not think that I have changed the code in this respect. Can anyone confirm whether this is unique to Experimental, or whether it can be reproduced in Standard?