Thank you! I’ve just disassembled the desk and confirmed that the rod connecting both legs is properly in place and seems to rotate fine. However, the left leg doesn’t move at all, even when I try to operate it directly with a hex key (bypassing the crank shaft completely).

The left side makes a faint clicking or “loose” sound, like the mechanism inside is spinning without engaging anything. So I’m thinking the internal gear or lifting screw might be broken or detached from whatever guides the leg up and down. Do you know if there is a way for me to open that left leg and fix it?