Patch Notes PTS 24.3
the new crane seems to have had a small problem since the last update. the crane arm doesn't move a millimeter, but the hydraulic cylinder and the winch points move.
it looks a bit spooky when a box is attached

Judging by the cargo bed and wheels on the Kenworth you're using mods of some kind. I cannot replicate the issue on my vanilla copy. This Season's PTS is over anyway, but in the future please refrain from reporting issues when playing modded.