That sort of cage lip-exploring is pretty par for the course. That's why you have to make sure you have screen lid clips, at least 2, but preferably 4.
I had a 15g kingsnake at 11-13" long get up onto an edge of a tub that was 12" tall... nothing in his cage at the time stood more than 1-2" off the ground and nothing against the walls, so I am still baffled how he did it without any height assistance from decor.
But point being... they will do that, especially as they get big enough to reach on their own, so securing the lid is most important. Corns seem to really like the tight space it provides far better than any hides, so that will probably happen again at some point.
Sent from my SM-G950U using Tapatalk