More info is needed , but yes, it seems like if it were chocked properly it would not have moved, and therefore "failed". Even if you we're on wood blocks and the TT moved it may have come off and bent the shaft. I'd bet it happens occasionally to others as well. I saw this product reviewed and didn't like the looks of it, but if the TT is chocked solid, and the brute is pinned properly, I don't really see how it could fail.
OP, sorry for your troubles non the less. Lesson learned as they say.