I am having the same issue.
I checked all the tubes and settings. Couldnt figure it out. got that weird error.
The worst is that the filament would then backtrack faster than my rollers and loosen a perfectly good tight roll. ugh.
so i’d hand tighten and try again.
I tried to add a little tension to the spool, manually, and as it ‘tested’ that the spool was tight, it started heating the bed/calibration and would print fine.
When i multicolor i have to put a little pressure in the spool and boom, it bypasses the test and prints fine. but god, doing this on a print with a few changes… isnt bad. Doing it on a bigger issue. OMG… nightmare.
It happened after the 1.08 firmware update. I backtracked the filament to the 1.07.05 but didnt fix it. The AMS firmware didnt backtrack from what I can tell.
Is it possibly a AMS firmware issue?