Seminal work by Cortadella, Kondratyev, Lavagno, and Sotiriou includes a hand-written proof that a particular handshaking protocol preserves flow equivalence, a notion of equivalence between synchronous latch-based specifications and their desynchronized bundled-data asynchronous implementations. In this work we identify a counterexample to Cortadella et al.'s proof illustrating how their protocol can in fact lead to a violation of flow equivalence. However, two of the less concurrent protocols identified in their paper do preserve flow equivalence. To verify this fact, we formalize flow equivalence in the Coq proof assistant and provide mechanized, machine-checkable proofs of our results.