I don't know HOW to reproduce it but on many occasions while playing both Chernarus and Livonia 1.19 experimental I have been walking and moving about objects, i.e. boxes, crates, doors, etc... and will get stuck unable to move. My character is running/sprinting/jumping but i'm stuck inside the object, or attached to it. If I jump and move about enough i'll eventually break free but it hasn't happened on 1.18 and is in the 1.19 exp branch.