"He who marches out of step hears another drum." ~ Ken Kesey
Not sure if this will help, but I had issues a few times when people were pulling ink from the top of the bucket without stirring--the top prints easy, but has crappy opacity, all the pigment drops to the bottom, so once the liquid on top is gone, the bottom is opaque, but stinks to print. That ink is so loose, I think you HAVE to stir the whole bucket up. If stirring well isn't SOP every time, try it out, it might help.