First, I am not exactly sure if it's a bug or a feature, but if it's a feature it will need some refinement to prevent deadlocks and an overall more human-predictable behavor.
There seems to be an issue somethimes causing ships to wait for clearance on a canal when meeting a ship that is travelling in the opposite direction.
It is not clear to me how and when this happens, the only thing I can say for sure so far is, that I have observed that situation many times around watergates and just now saw this happening without a watergate being involved.
In the worst case, this bug can cause permanent deadlocks as at least once occoured in bridgewater-brunel so far.
Further, overtaking doesn't seem to be possible on canals either. I guess that's intended?
Is this in extended? this could happen if the next tile is full: There can be max ~255 objects on a tile. Also planes circling about do count.
Oh sorry, yes this is related to extended.
This is definitely not related to full tiles. I had observed this with exactly two ships.