not a fade out
That doesn't look like a fade-out to me. It looks like your machine is dropping one of the jets.
After your "fade-out" happens, run a jet test. You'll be able to see which one is failing.
It could be a dirty jet, head, print head. Whatever you call it on your machine.
You should also check the caps. Are they actually cleaning? Or are they dirty too.
Dirty cappers can deposit whatever they have on them onto your print heads.
This would be your starting point.
If not, then it gets more complicated.