Yes, I've noticed this aswell and so have some of my mates in my clan. We frequently call those players out while we battle via VC so everyone is aware of them and can act accordingly when encountering them on the battlefield. That helps to some extent.
Why is this so? I can only speculate. I feel that recently (past month), "lag" has increased. And while those players are not your typical, obvious lagger, because they do it (as you say) consistently, I do believe it is well tempered and controlled lag. That basically happens in every competitive online game: Players will find a way to manipulate their connection (mostly LAN, as that gives you the best power over your connection) in a way that it benefits their performance in relation to the other players in the room, without disconnecting. That's why you sometimes have strange DCs in weirdly dominating S+ teams: Some player failed in keeping up their trick and the connection crashed on him. Those are not accidental crashes that happen to people on awful wireless-connections: That's failed lag-switching.
