I wonder how much acid was absorbed by the gelatin in the film.

I would think that at the very least it might affect the results by changing the initial pH of the film plus developer combo. If you have a choice of developers, I would recommend something that gives a longer developing time. Having excess developer in the tank might be a good idea as well.

I have never made that mistake (there has to be at least one I've missed) so I would be interested to hear from someone who has..

Assuming of course that Chris isn't speaking from specific experience.