Plot hole: Al comes home from work. He purposely doesn't look in the kitchen, so he can act like he's surprised it isn't Peg that brings him a beer. Steve talks and Al acts surprised that he's there. When you walk in the front door you automatically see the kitchen.
Suggested correction: It's quite possible to do this. My house has a similar layout: front door opens into the living room, and the kitchen is at the back of the living room. I can come inside and walk to the couch without paying attention to the kitchen. Plus, Al is cranky after work - he says "Ah, what a day" - and he is focused on getting to the couch and relaxing.
This is the only episode where Al does this... Just because he knows it's Steve and not Peg. Pretty obvious.
Just because something is only shown in one episode, that doesn't mean it has never happened before. And because he said "What a day", it seems that his work day was especially frustrating, busy, etc. It's reasonable that he could focus on getting to the couch, not bothering to look at the kitchen.
Poppy's By the Tree (2) - S2-E2
Plot hole: Al and Peg are upstairs with the killer. Both of them are screaming, but downstairs, you can't hear anything. Everyone is sitting around talking. It's not until Al and Peg scream again that everyone runs upstairs. And you can tell the screams were "on cue" also.
