I've had this same bug several times since the new update and not before. The server host person I play with has not had the issue. Here's a pic of my friend stood on a plank that I cannot see myself. When I stand on it, I sort of fall through (my client thinks I fell, but my friend says I have not).
The only workaround I've found is to log off/on, but very often I cannot rejoin (my friend doesn't show up in the server list and they have to quit their game and relaunch.)