Don't know where Troop & Anchell got their "facts" about what fixer Mr. Hutchings recommends, but in his book "The Book of Pyro" he mentions that he used Kodak F-24. Of course, that book was written a long time ago and his materials may have changed...just sayin'. Oh, and F-24 is an acid fixer that I've used for many years with pyro developers.
Some of these issues arise because people observe one thing, and then land on and share what they think might be the cause of that happening.
The observation can be more or less correct, even when their explanation of the cause is not.
I have one fix left in my alkalai fixer then its Adofix all the way. I do expect my Adofix to go a tiny bit brown but I am presuming that isn't a problem