A white lie. But for what?

Husband went the other day to get pet supplies and said he picked up food for my pets as well which I usually do. I thanked him. I was cleaning up and saw a slip for pet smart and the food was ordered by his sister as a gift for us which is kind. I just wasn’t aware she gifted it to us so I could thank her. He told me he got it from Walmart and then when I asked him today he said it was a pickup from pet smart his sister sent us. Like it’s a very stupid thing to overthink but why not just say it like it happened? There are many instances that are so dumb that I catch him in a lie to make himself seem like he’s doing everything. He often exaggerates about how great he is and I’m just asking myself “but why?”. It’s instances like this where I just think I’m crazy because I know what he says the first time and then changes it. I feel silly for picking at this and I’m not gonna say anything - it’s just noted in my head. I told my father and he told me to stop creating problems in my marriage with someone I chose to be with. I need advice. I think I’m going koookooo