I assume by 'marker' you mean in this case 'dummy half'?
In any case, DCE was nowhere in position to even be considered dummy half, regardless of who grabbed who. Bit different if he's grabbed, pushed or knocked as he's getting to the ruck but seriously, he was a mile away and there were other Manly players in far better position to pick up that ball. Not the refs', bunker's, or Nightingale's fault if DCE called dibs when he was in the worst position to do so.
DCE obviously learned nothing from Jamie Lyon too. Doesn't he know the proper way after you instigate something and the other player lays a hand on you is to throw your arms out while screaming to the ref, then falling to the ground for maximum effect?
Marker/ dummy half. Yes, dummy half in this case. You'd assume most tries with interference from one side would come with interference to the defensive side, so marker in most cases.
We can't tell if it was the ref's fault, or DCE's, or Nightingale's, (or Trbojevic's, or Widdop's, or whatever) since they weren't allowed to examine it. Anyone saying that DCE was at fault or Nightingale, or whoever, is making a moot point. We couldn't check. The bunker was not at fault (they never are), they followed protocol.
I thought DCE was theatrical enough there, and the great Jamie Lyon was but an amateur compared to Terry Hill. The very fact that players will carry on to get an advantage, shows that we should limit opportunities for "professional fouls", and having a "bunker free zone" does not do that.