Since today I have a problem with my CR10 V3. As soon as I start a print the printer goes into "pause print" mode and for a fraction of a second will show the "change filament" error and then goes back to pause print. I have the filament running through my filament-sensor and the LED in the sensor is on. And as long as I don't start a print everything looks fine. No "change filament" error message. And every few seconds the "change filament" error will pop up for a fraction of a second and then back to pause print. Only if I remove the filament the display will show "change filament" (as it shoud) continously. But if I put the filament back into the sensor, the whole thing start from the begining.
This has happened to me after 3 days of printing. It's the filament sensor, its picky. You would not notice it but it goes off for a msec. Lots of users report it. I just follow them and stick a piece of filament (and tape it to secure), and not run the filament through it and not use the sensor at all.
@billyc That is a good idea. You can also disassemble the filament sensor and reflash a firmware without the sensor.