Naval Pathfinding failure

[mimo]

Here is a simple case of a naval pathfinder failure. On the first screenshot the computed path is shown, which tries to avoid the two floating treasures. But on the second screenshot, we see that the ship is nonetheless blocked

A trivial workaround (which imo also makes sense so should be done anyway) is to make these small foating treasures to not block movement. But i attach here the corresponding saved game (saved just before this happens) for r21168 if somebody wants to look at it, as this seems (maybe wrongly) to be fixable. (The warnings appearing have no effect on the bug, there are there only because the game was started with autostart).