I was thinking it was going to be something unjustifiable.
But man the "bad" challenge is actually really smart. He sees that the point men has his head down and spinning around so tries to surprise him with a poke check and hopefully force a breakaway. It doesn't work, he misexecutes and misses the puck or the pointmen just makes a great play. But I mean clearly his intentions are good and a play a smart player tries to make. It was a good gamble to take with a high reward.
In terms of going back I think he just assumes that he is taking the wingers responsibility now since he was up by the point and he probably assumes one of his teammates covered for him.
Should he have gone straight back to his net? Probably. But he is offensively tilted and maybe saw an opportunity where the puck was going to be wacked out wide to start an odd man rush.
Offensive players will sometimes cheat for a rush. Don't think it's any deeper than that.
The problem with the pokecheck is not that a pokecheck is wrong in that situation, it's that he does it before he can even reach the puck, so his opponent can easily read what he's doing and walk around him. Pokechecks should be disguised, for the same reason that goalies have to hide it if they plan on doing it. It's not a big deal, just a somewhat baffling technical error, you'd think an NCAA level player would have better technique.
The more worrying problem was when he got back into the play, he clearly has five opponents in front of him going to his net. The PK winger role there is also to go to the net and tie up a man. Being able to count is really important. I don't mean literal counting, I mean that players with okay hockey sense would all know if there were five players in front of them and zero behind them. It's possible that Lev knew and just made a poor decision.
Being able to know when to cheat and when to play defense is a really difficult thing. Successful rovers in the NHL all have incredible hockey sense. I think if you try to have Levshunov play this way in the NHL he would be picked to pieces.
I don't think Lev has the hockey sense to be a #1 with any playstyle. There are plenty of D in the NHL who have #1 type tools. There aren't many that move better than Mike Matheson or Thomas Chabot, but those guys aren't #1s because they don't process the game well enough. Same with Nurse and Provorov.