I was experimenting with water and watermechanics for some youtube videos and did see a graphic bug with the flowing water. I dont know if its only for me like this or if its a known problem but I didnt find anything related in this forum. In this video you can see what I mean (at around 26:50):
I know that water is newly added in alpha 10 and will be further optimized. Maybe this still helps.
it probably has to do with the hearthlings collision box (or whatever they’re called), because that makes it so that there is something to set the ladder against.