Game proper almost unplayable - errant NPC and hero behavior

While in the game, controls become unresponsive and characters either stop moving, move in straight lines or WALK BACKWARDS at high speed. Lasts from half a second to a few seconds. Can be seen in my replays usually followed by a comment like "WTF did anyone see that ?" and "Is anyone lagging AF with low teens latency reported".

This board is the definition of crying wolf, but take my word (as someone who did QA for a living for long time) this warrants a closer look then all.