10mo new rescue peeing in the house

Hello! We adopted a puppy on 02/28, and he is now 10 months old. He’s a schnauzer mix, we think with some border collie. He’s been very good, picking up commands fast, generally taking well to his kennel. However, this week he’s had 3 accidents in the house: two of which were today while I was in the room. There was no behavior beforehand that made me think he had to go outside, though he probably had fewer potty opportunities today than normal as he didn’t get an evening walk due to bad weather.

Is this just him being a puppy and being new? We’re going to start giving more regular potty breaks and rewarding with treats when he goes potty outside or asks to go outside. Up until now he’s had no issues holding it overnight, or during the day while kenneled (we work all day, so he has 3-5 hours of kennel time in the morning, then a 30 minute pee and play break with a sitter, then another 4-5 hours of kennel time). As soon as he comes out of the kennel he goes outside for a potty opportunity. Fridays are a different routine because I don’t work so I’m home most of the day. Any insights would be appreciated!