Try the colour calibrate printer to re set printer accuracy. This is used on initial set up of the machine, you must have seen this.
I do this half yearly and it showed up a recent issue very well, as you get a print out of colour swatches that the printer uses to sort itself.
These are clear blocks of colour from the print heads and in my case showed a muddy red channel just when I was struggling with a new graphics card, monitor calibration and custom canvas profile all on a weekend.
And it got stuck on one calibration run due to a small crease in the profiling roll, would not end job so had to pull the power. OK as print carriage at a standstill.
I have never engaged the cleaning A or B manually before.
It took 2 A cleans,1 B clean to clear the contamination from the head.
Nozzle checks show nothing and the ink carts were clean.
Supplier says they have seen this before but no understanding of why it happens.
B clean sorts problem.
I do not print commercially and the printer is often idle for a month but with the power on and a sine wave UPS so that if there is a power failure it will still be on when this is restored.
Plus to save a crash while printing.
It is 4 years old, original print heads still in place.
I had the printer standing for two months while away over the winter and power off as I wanted to cover it.
On start up all looked good. Seems that there may have been a slight ink
cross contamination at the heads while idle.