Ofc it may happen in all modes, but solo/PG modes ensure that it will not be directly opposed (except for vote, as that's not being influenced by game modes) and may not spotted in time under certain specific circumstances (i.e. scrap turmoils).
5C can be intentional work from the opposing powers (and it's fine IMO)
But it can also be this hypothetical situation where player X playing the PowerPlay as they see fit, disregarding the "leaders" of PP player groups. And there can be lots of such players creating a "buzz noise" that sometimes may cancel itself while other times may look like sabotage.
I mean (still hypothetically) who made you a PP leader? Not me. And you cannot dictate me how to play my own game.
And if my playing is not aligning with your idea/direction of how PP should go, you may label me as a fifth columnist.
IMO, it's not a good idea to design a system where multiple player factions have to work together and have all of them coordinating to pull the the sledge in the same direction.
It works for BGS where usually it's a single faction/squadron and a single leader, but it's not that easy when many factions and many Egos have to align together.