bad seal at ink carts
well then start pulling ink. start at the damper and work your way back. just FYI my C had a broken nut just after the cart station so look there. The brass nut like broke in 3 parts they will do that from stress they move a little when pumping.
I'll do a little plumbing work but I think the issue relays on the new Mutoh cartridges \ design.
Thanks!