water-like stain from HP Latex 300 printer

[Pideas]

I am running a HP Latex 300 printer and using 3M IJ35C media. I have run a few jobs now with a full solid - black, red or dark green. I have noticed that there are marks on the prints after it dries. I cannot tell what it is and what's causing it. I am hoping someone has encountered this before so I can remedy the problem. Attached are some photos. Any ideas what might be causing this?

 

[bannertime]

Likely media contamination. It's not really in a pattern that would be a mechanical issue.

 

[flyplainsdrifta]

id say media as well. try a different roll from a different lot number.

 

[Pideas]

Thanks for replies. I will swap media and see if I get a different result.

 

[Reveal1]

Looks like media, but I wonder if it could be an optimizer problem (too much?) Easy to check by reducing in profile.