I have never heard this claim before and also have doubts about it's veracity. I personally cannot think of any reason that it should be true. In the past, stopbaths were only needed when using developers with a high concentration of carbonate. No one uses such developers anymore. The purpose of the acidic stopbath was to prevent developer carry over from raising the pH of the fixing bath.
Originally Posted by pentaxuser
I have been using a plain water rinse for most films for many years without any adverse effects that I can tell. The only time that I use something else is when processing soft emulsion films like the Ekfe ones where I use a chrome alum hardner.