I just don't believe it at all. In that batch, maybe they'll stop fermenting it because of a combination of factors with the trigger being a high percentage of glucose to start, but maybe not. If John is right though, wouldn't every kit-and-kilo batch that Aussie brewers made be ridiculously sweet? Those are more than 30% glucose, and while I haven't heard much good about those types of brews, I've never heard that they were cloying.
I grow yeast on glucose all of the time and this has never, ever happened to me. I'll have to talk to John about it and see where he's getting his info and what the parameters of the experiments are. It may be that when the source says "polysaccharide" they are referring specifically to more than two sugar molecules, since a two sugar chain is typically just called a disaccharide and not included in the polysaccharide term.