Yellow background on print outs

[mga]

Good day

I have a MP C2011 which is producing copies and prints with a yellow background. I suspected that the toner is generic. But the client is 'claiming' that it is original. The PTR is has yellow toner on it. The Yellow PCDU has done 27k prints only. Please see attached pics. Has anyone ever encountered this issue?Attachment 50509Attachment 50510Attachment 50511Attachment 50512

Don't waste time just replace new oem pcu and developer assy job done