Rainbow boa likes being upside down

Recently got a rainbow boa and he’s pretty calm. Very active and curious of anything. He’s got a great demeanor. I bought him from MorphMarket he’s about 5 years old. I’ve noticed he likes to go upside when he’s exploring his tank or even if I’m just holding him. He’ll only do it for maybe a minute or so but I’ve never had any other snakes do this. Boas or pythons or any other type of snake. Is this something I need to be concerned about possibly?