"Display Drag Factor" error reading 999 on PM4

[toorow]

One of the gyms I use has 3 Model Es, all with PM4s, and on one of the PM4s, when I go to "Display Drag Factor", for a split second, the right number appears, but after the split second, 999 or 998 appears, and stays at that number, the battery says 65%.

Is this an easy fixable problem, in the highly unlikely event that the other 2 ergs are being used when I want to workout??!!

[Citroen]

Upgrade the monitor firmware to V318 (or V29 if it's an early model of PM4).