I checked with the customer, they are genuine HP carts. I think that shows in the supplies status screen shot.
The problem is intermittent. It will work properly for a day or two and then do the bars on a couple of random pages. Given the spacing it may be an intermittent electrical fault that affects all of the carts at the same time. ie the spacing appears to be about the same distance as the spacing between the carts.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".