I jump a lot climbing ladders, I dunno why, it doesn't help but I found that when I jump, with the double jump boots on, I will stop climbing the ladder and start sliding back down and I can't go back up until I get to the ground; this also happens when you use the grappling hook; after you use it, you can't finish climbing up the ladder.

I also had something happen (that hasn't happened before) where I fell down the ladder in a 1x1 hole, it almost killed me due to the height, where it's impossible to fall down off the ladder. I was changing gear at the time but I tried to do it again and it didn't happen.

Minecraft in Linux: 1.19.4
Forge, 45.0.41
Grappling Hook: 1.19.4-1.19.4-v13
Cloth-config: 10.0.96
Java: 17.0.6

1. Climb a ladder
2. Jump or use grappling hook (and I'm sure other parts of this mod that I have not yet unlocked)
3. See in ability to go back up the ladder.
4. Repeat test without shoes on, see you can still climb the ladder but grappling hook still prevents you from climbing.

I'm having issues like this as well - I got "Wall Running" enchantment on my boots and I end up insta-dying/taking a lot of damage randomly when using ladders. I take it this is probably the same bug. Unfortunately, I'm playing the mod as part of Create: Above and Beyond so I'm not sure which mod version I'm using.

Chiming in to agree, yeah this is a big issue. I use the grappling hooks to explore and if you are in "grapple physics" mode after you detach, ladders don't work, and even though you look like you're climbing down the ladder, the moment you touch the ground it instantly kills you from fall damage.
I'm assuming the double jump boots put you in grapple physics mode, which is why they cause this issue as well.