Z6100 Printhead - All Nozzles Out/Clogged/Not Printing

[BPG1]

I've been having a recurring problem with both of my z6100s. One color of the printhead stops printing entirely as if all the nozzles are clogged. See photo attached of a newly installed light cyan/light magenta printhead, where the light magenta doesn't print at all. I had just replaced a printhead that was doing the same. Running the cleaning procedure doesn't fix, but I've occasionally had temporary luck by restarting the printer. I've tried cleaning the contacts and reseating the printheads, but that does nothing. My 42-inch z6100 currently has 3 printheads doing this (1 Yellow and both Matte Black). Fortunately I've been able to work around it since I don't use the matte black and I can add an inch of bleed on top of the prints and the second yellow printhead compensates for the rest of the print. There are no error messages and it usually doesn't tell me that the printhead needs to be replaced. Sometimes replacing the printhead solves the issue and sometimes it doesn't.

I was going to try and prime the ink tubes, but not all of the ink cartridges I have available are within the correct volume range to run the procedure. Hesitantly I did use a syringe to draw a small amount of ink from the light magenta tube and it seemed like it was flowing fine - no air or clogs.

Anyway, I was just wondering if anyone else has experienced this and had any insight. It seems to be happening more frequently, and I'm thinking it's more of an underlying printer problem versus having bad printheads.