I noticed that, and know that even after this commit there are lots of places with lingering issues.
I thrashed a bit with the liquid vertex placement and tessellation, and obviously got it wrong...
A picture from in-game: http://img829.imageshack.us/img829/4180/gamey.png Taken from below, the terrain is culled.
Now one from recast, the same location: http://img812.imageshack.us/img812/2462/mesh.png Taken from above, with terrain polygons excluded from the build process.
I circled the area of interest - in recast, notice that all of the edge-quads' bottom-left triangle is missing.
This, combined with the above issue, probably means someone needs to redo the liquid part
Thanks all, for continued efforts!