Description of the issue:

Cannot climb a metal ladder (IE version)

Versions & Modlist

Forge 36.0.46

EDIT- I believe it is an issue with Forge and IE. I downgraded my Forge version to 36.0.41 and the ladder works again. Video below is with 36.0.46.

IE version 4.2.2-132
Modlist: https://pastebin.com/T9kCmE4h

This is the direct result of a change in Forge:

MinecraftForge/MinecraftForge#7535

Apparently vanilla has a Tag for climbable stuff, so I guess we gotta use that...