This is going to sound counter-intuitive but I think our problems putting the ball in the back of the net is partly down to our problems at the back.
It's similar to Pep's first season where we didn't struggle to create chances, would dominate games, miss some ridiculous chances, and lose to the opposition's only attempts at goal. Think Chelsea at home 2016/17, battered them, KDB hitting the bar with an empty net from 8 yards, should have been three or four up, lost 3-1.
Last two seasons where we've been solid at the back we have been more clinical and it's more or less the same team going forward in all these seasons.
Maybe we feel more under-pressure in these games to put our chances away, knowing we have to score as we will concede at some point, the longer the game is in the balance the more the pressure ramps up. If we go a goal or two in front though, the pressure releases and we batter them, like Villa away.
Maybe I'm reading too much in to it but teams at the moment know they can/will score against us, so if they just stay in the game they get a result. That's two games in a row where the only tactic the opposition has had is to defend, and both games we have contrived to lose.
I'm not concerned long term, we are battering teams and creating chances, and if we can just become a bit more solid we win these games comfortably, especially if the other team know they will have to do more than just sit back and wait for our mistake.