Recurve Bow + Black Cleaver interaction bug

Purchasing Recurve Bow, or Runaans Hurricane, followed by The Black Cleaver, leads to autoattacks applying Cleave twice on a single attack. The interaction is specific to purchase order, and may be reset to an expected interaction by further purchases of items or putting points into abilities.

I have reason to believe the bug is specific to purchasing items that add physical on-hit damage, and have seen it happen with Blade of the Ruined King , although I am not able to reproduce it reliably.