I think either Dest or Umiron said that Harmonious removes a small amount of pulses from lag, whilst lag bug issues I witness half the lag in question, which is harder than Harmonious. So I'm inclined to believe that Harmonious is not the culprit here.

My SWAGs are: memory leaks, nage-waza tuning byproduct (as it was the only lagging move that was widely discussed at the moment).

At the same time, like with the recent qhcf log, one suspicious case was wimpy firing during lag (I believe it does fire mid-lag, although rare), the other case was heavy armor shaman halfing the trip lag against gank (it's pretty awesome if heavy armor has a chance to actually HALF the lag), but those are good examples of something that might look as buggy behavior to a biased beholder actually not being such.