Affect dye stability? This is interesting. I though the blix and a generous final wash would remove all developer from the coating. After all, there is no stop in the machine process, if I'm right?
Anyway, I've never had any streaking with citric acid in trays used for the whole printing session and dumped after that.
Couplers are dissolved in coupler solvents to disperse them in droplets in the emulsion prior to coating. During processing, the CD3 migrates into the droplets as either the oxidized product forming dye, or the unoxidized free base which can remain.
This free base, if carried through the process with bad agitation or exhausted blix or bad wash will cause a pink stain and loss of dye. The stop bath is there as a safeguard as this problem is also related to the blue/cyan stain you get in rotary processes with no stop. The rotary (drum) processes such as the Jobo are prone to this problem.
We wanted to take no chance with bad dye stability and so if you see streaking on any prints or a cyan dmin it is indicative of poor removal of developing agent in the paper and needs a good stop. Acetic acid is the best choice for this IMHO having worked on the problem through vacation to make dye stability better for you. This is not something you would hear about generally because I feel bad about the problem. It cropped up after release and we had missed it due to our high quality processing. Medium to poor processes show this problem.
So, why take a chance.
Besides, a good stop gives better whites, longer life to the blix and improves the wash rate.
So, there you are! Remember that all processes, water supplies and peoples work flows are not created equal. The process is aimed at the worst possible conditions now, one that I personally missed way back then and am very very aware of!
BTW, one of the reasons it was missed was that EP2 was to have been EP3 with a final stabilzer. This pH 4.5 stabilzer with Citric Acid, was the final bath and did do the same job after the blix had first shot at the CD3. Most customers did not want the stabilizer so it was eliminated from the process thereby revealing the problem too late.
Interestingly, this pink stain appears and then vanishes so that was another reason why we missed it. But, once the process has begun, it does not stop even though the prints may appear normal.
If you wish to see the pink stain, use an acetic acid stop repeatedly without dumping it, until it is nearly exhausted, and it turns bright pink. Addition of sulfte (which is in the blix) eliminiates this pink color. If you add a pinch of sulfite to the stop, the pink color vanishes. Same reason as it vanishes in the paper. It is being sulfonated in this case by the Sulfite. Good blix was intended to prevent this, and so a well replenished fresh blix is also another reason why the photofinishers see little of this type of problem.
I hope now that you see the ramifications of color system development and the common problems you may experience if you make unwarranted substitutions. Good luck.
PE