Ferricyanide, when placed in contact with developer, gives instant FOG due to oxidation and coupling. Therefore ALL color processes that use Ferricyanide must use a good wash and clear after the color developer. This clear is an acid stop bath with some Sulfite in it.

The Ferricyanide must always contain Bromide and is best when acid.

And, when conducting image keeping tests, I have had people swear to me that the image was unchanged until I showed them a check example that had been frozen while the test print had been stressed with light, heat, humidity or all 3.