Put the summary of the bug you're having here

What I expected to happen was...:
Climb down the scaffolding 

What actually happened was...:
Remain in place and cannot climb down

Steps to Reproduce:
1. Place a ladder above scaffolding occupying the same x and z coordinate and 1 y coordinate higher than the scaffolding
2. Attempt to climb down the scaffolding by pressing shift
3. Player remains in place and is now "stuck" on the ladder