I have a problem with Epson xp-610. The printer is converted to print with sublimation inks.
1. I know it's not meant for that, but it works just fine over 6 months now
2. The cartridges are refillable
3. The problem is that from time to time a color disappears completely /Yellow and Cyan so far/
When I print nozzle check pattern there is not a single dash from the color other colors are fine

The print head is not clogged.
The ink cartridge is not clogged.
Head cleaning does not resolve the problem.

The only thing that resolves it is to refill with more ink let it settle for 5 min and when I print the nozzle check not one dash is missing.
I found a way to work around the problem but it drives me crazy when I need to print something on the spot and have to take the inks out and refill.
So my question is does anybody have an idea whether the problem is with the cartridges and their chips, with the vacuum or the printer itself

Thank you in advance!
Best regards!