I've processed miles of ektachrome in different types of machines (although not the CPP-2) I've never had much luck with one-shot rotary processing but in dip and dunk and roller transport seasoned replenishment systems, a blue plot usually indicated a Ph problem in the color developer. A small (TINY!!!) addition of sodium hydroxide was the prescription.
But, if your 4x5 is coming out consistantly good I can only think that it might be the emulsion batch of the 8x10 film.