Puppy regression at 5 months old

Hi everyone, we brought home our sweet and playful Beagle puppy when he was 2 months old. He took to training very quickly learning all of his basic commands and learning to love his crate. He hasn’t had an indoor accident since maybe the first week he was home.

However, now he is nearly 5 months old and nervous to see some signs of regression. In the past 2 weeks alone, he has peed inside of his crate 4 times, which he had never done before. 3/4 times we got absolutely no warning – no whining, growling or barking. One time he barked but we thought it was demand barking which he’s also recently picked up.

Any advice on how to manage this? He was leaning into his crate so well and still does otherwise for all of his naps and bedtime. What other signs of regression did you see in your pup at this age?