AIBU yes is he BU no
Ds (12) washes up every night.
Last night he didn't wash the slow cooker pot and a couple of cups/ice-cream bowls that were left in the living room (pudding on the sofa later on in the evening rather than straight after dinner).
This morning I text him and said in a jokey way that I was saving the bits he missed for later. I.e natural consequences.
Ds came home from school after film club with his mate. He came in and asked if he could do the bits he missed with the rest of the dinner stuff later as he brought his friend home. I said yes. In my mind there's not a lot of difference and he will still have the same amount to do taking the same amount of time.
Dp (been together a few years, he's only been living with us for four months) has come home from work on his turn to cook dinner and is not happy. Dp is annoyed that DS is playing playstation in his room with his mate and hasn't washed up yet. I said I didn't really think it mattered as he will still have the same amount to do. Dp is now annoyed that ds hasn't been punished (his words) and felt that him washing up twice was the punishment and is unhappy that I haven't enforced it.
I don't believe this is the big crime of the century which needs a punishment. Natural consequences and a don't take the piss and do it again is fine imo. Dp is now reacting like this as it's a personal problem and telling ds he is not impressed as it's not the way he would have done it and is taking away a pound out of his pocket money.
I don't want to live in a putative overly harsh and critical home. I enforce boundaries and am pretty strict. If I say no DC listen. They don't need me to be overly harsh to get them to behave.