9900 and piezo pro problem - cold and violet tint in neutral

Hi I am using an epson 9900 printer and piezo pro system. Recently I have a problem with tinting to a colder and slightly violet when printing with a neutral curve. There should be no mistake when refilling the inks. The printer has not been used for about two months. The cartridges are not shaken during this time. Before this long pause, there was no problem, I think. Is it possible that the inks have a problem after settling. The inks themselves are more than a year old in the cartridges. The printer also behaves strangely when it is turned on and does not print for about 15-20 minutes - it falls a sleep and there is no possibility to do anything on its menu, it can only print. The menu can be viewed, but does not accept commands.
Thank you for your attention!

Aside from the falling asleep part, the problem is that you need to agitate. Agitate the carts at least once a week (a LOT). I do twice a week, Monday morning, Wednesday morning. You have old settled ink. Neutral-type inks will show shift more than color inks even though the settle is occurring just as much with color inks. Agitate!

In this case you need to agitate and run several full cleanings or print out at least your cool inks with QTR in calibration mode (2x 40x90 inch prints per channel on some cheap paper like a roll of non-silicone butcher paper).