Thank you for noticing it, you are totally right ! I forgot to mention on the page (it's in the video) that when you cut grass with the sickle, wood appears because I still haven't done the cut grass 3d model, so I think that you were just cutting grass ! And sometimes you get pushed because the wood appears too close to the player so there is a kind of collision, there is the real problem haha.
It will be resolved in the next update, thank you :)