That's because of a combination of the level seams and now-outdated ledge grabbing code.
Basically I made this demo before Unity came out with it's own Tilemap system so I built my own and it was great for the most part but it uses Edge Colliders instead of Box Colliders (because you could "trip" between tiles that way and it'd stop movement for that frame), as for the ledge grabbing it used Raycasts and now uses A BoxOverlap instead making it more reliable and fixes this issue.
So not intended, but doesn't break anything either.