I've seen something like that and it was caused by some dust on left of machine (in the door)...
Do you see these smudges when using tray 1, tray 4 or all trays ?
I seem to have this hazy cloud smudge looking problem in my prints. Some paper give it more than others, mostly on thinner stocks and definatly on duplex jobs. I am not sure what could be the issue. Not sure if maybe a drum is going bad or the fuser or something else.It happens at random all over the prints.
I need help urgently!! Hopefully someone knows what this is.