Why did Jobava do that?

Rc6 at the end? What? I understand he was "trying" to win but seriously that is just reckless.

just a miscalc :p obviously thought the connected passers on the 6th would be strong enough.
still yeah, nothing is really being threatened so he wouldn't achieve anything either if black didn't take. silly things that we do sometimes

He was playing aggressively trying to win from a drawn positon, and he probably did not register that after rc8 the pawns are stopped, and the resulting position is bad for him. Even grandmasters blunder. Had he stopped to play the line out in his head for like 3 more seconds he would have not risked it.

It seems to me Baadur missed 38...Kd8!

Not the first time that Jobava misplays a rook endgame against Ivanchuk:

@chessanalyst how did you do that with the movetimes and the switching eco descriptions?

Why did black resign in this second game? It seems black can hold the pawn's endgame.

#7 @tpr After 43.Rxa4 bxa4 44.Kc4! the white king jumps into the square of the a4-pawn and now the black king can't stop the White's kingside pawn majority.

Yes but 44...Kc6 and now what?

#9 @tpr 45.Kd3! remaining inside the square of the a4-pawn. Now the black king can't stop two simultaneous threats: the breakthrough e5-e6 and the advance of the c-pawn.