I checked out problematic pathfinding place from my previous comment and now JellyHailey indeed can climb onto that small ledge but she won't chase the player in the small tunnel that you crawl in after this ledge
This isn't bothering me but I'm infroming you just so you know.
Also, there is some minor issue with the text in level 17. After defeating shellworms and obtaining the key from Ivory if you try talking to her again she'll say that she needs to send a report and that you should hurry up and get rid of the shellworms
Almost forgot, sometimes during the animation Jellyfish goes into idle mode