I'm pretty sure I've heard Austrians give that argument before, but I don't think it's the only one. I remember Block talking about how Austrian Business Cycle theory needed to be revised because of problems with the Hayekian Triangle.

I found the working paper. See, in particular, sections 1 and 2 and the summary. There's too much to quote concisely, but Block's main point in section 2 is that the aggregate Hayekian triangle doesn't have any microfoundations. He wants to be able to derive the aggregate Hayekian triangle from the Hayekian triangles for each specific good for each specific agent. But this isn't a reason to reject the model outright - very few scientific models have complete microfoundations (all the way down to physics). That doesn't mean they won't make accurate predictions. Microfoundations tend to help, of course, but they aren't necessary.

Disclaimer: I am not an advocate of the Austrian Business Cycle theory. This was just for illustrative purposes.