Mekanism version: Mekanism-1.7.10-8.0.3.203
Minor issue, 99% sure it's related to the lang files.
Instead of showing the display names, e.g. Mode Switch and Baby Skeleton, the game or mods show strings like key.armorMode
, entity.Mekanism.common.BabySkeleton.name
or simply BabySkeleton
.