Do you remember where we can find this few publications?
This a very common problem but with very little stuff about it...
Let me see if I can pull up the archive relative to this. It's been a number of years...
I had a top ranked junior move to Florida to train...only to come back to me a year later and he was doing exactly what the OP was describing..which none of the pros in FL caught. And this was a top 400 ranked player! (He came back and said while his serve speed of 120 was fine, it was his second serve that was just giving him fits and many double faults.)
The first time I saw him serve, I said, "A.J...you are shifting your grip in mid swing, effectively moving towards an eastern forehand grip! You can't get the kind of spin to have a huge second serve."
We worked with him on this, and his serve immediately became huge when he began feeling the serve maintaining his continental grip.
(He went on to be Kim Clijster's hitting partner for two weeks at Indian Wells when she became #1 in the world...so not a bad player...he was on the ATP tour for awhile too.)
Needless to say, even some higher skilled players fall victim to this habit!