My guess is its an interaction with the ult and the new dash check, but also it seemed to only be happening to McGinnis throughout the match?
On top of that me and my teammates were randomly hearing Heavy Melee sounds(Schizophrenia update).
Several of my friends have had this problem
pak01.cpk / dl_streets.vpk is corrupt. Verify integrity of game files.
Usually to solve this my friend would try deleting some random file for the pak01.cpk and then delete dl_streets for the second...