I just did two rolls of ECN2 film in C41 chemistry with developer switch (mixed the real developer and it was a success!) but after the first roll the fixer bath turned slightly yellow and started reeking of rotten eggs and other foul things (it stinked already when mixed but not that badly!). It was plain nasty. I did a proper wash after bleach. The fixer worked OK for other roll, though. Is this normal? The fixer and bleach were Calbe RA minilab ones.