Diagnosis
The memory got corrupted, or you're accidentally in programming mode. A full reset clears it all back to factory.
How to Fix It
Hold down the 'M' (memory) button on the handset for about 10 seconds. You'll see the display start to cycle or flash. Keep holding until it stops and returns to just showing the height. All your old presets (1, 2, 3, 4) are now erased. To set a new one, move the desk to your desired height, press and hold 'M', then press and release the numbered button you want to assign while still holding 'M'. Release 'M' after.
If That Didn't Work
Try a power cycle reset. Unplug the desk from the wall for a full 60 seconds. This resets the control box's brain. Plug it back in and try the memory reset procedure again.
Heads Up
Be precise when setting new memories. If you press the number button before the desk fully stops moving, it might store an in-between height. Wait for the desk to stop completely and the display to settle.