Print quality issues with some solid colors

I am not sure if this is an issue with solid colors but the colors are spreading out when printing solid colors. See the attached files. This problem is not consistent. It has happened in the past with black on the Coca Cola logo. I am suspecting something to do with prints that have red in them. I have tried cleaning all print heads too but nothing is helping. Can someone please suggest a solution?

#1 Hi faridsk, this "effect" happens when optimizer printhead isn't working...check Printhead status plot to be sure but sometimes the plot is OK, but prints are not...

I just replaced the optimizer print head and the issue seems to have gone away. Thank you so much for your help.