No need to toss the banhammer around because someone might try and abuse wording...
I personally pointed out the awkward wording as I wanted to know whether it was infinite growth, or a mishap of typing.
But seriously... would it really have been broken? Giant Potential only counts half other hd, so it would take ten more to grow a size category. Whoop-dee-doo, at that point in the game all it does it make you a bigger target. My brain is so far removed from epic play I honestly never even considered anything past 20.
I don't want to grow!
If a monster class would make you grow but you would rather stay in your previous size, you may instead simply gain a +1 to a physical stat of your choice.
You don't have to grow a single time, you could just take the free stat boost and be a really tough Medium creature. Though the newer wording looks better.
I'm glad mine and FireInTheSky's pickiness helped you clear up the confusion we had.