Sometimes they just like to wander. Every morning my panther wakes up, basks for a little while, and then parades down to check out the lower half of the enclosure. Then he'll eventually climb his way back up and stay up high for the rest of the day. They're curious and like to explore, so it could be him reacting to the additions to his digs.
However, staying low all the time can indicate illness. So I would just keep an eye on him to make sure he is acting otherwise normally