Location:
Tooltips | Mod: Ender Utilities | All 3 Inactive Ender Cores

Exact fix:
Change "Ender Crystal" to "End Crystal"

These are base tooltips added by Ender Utilities.

I could remove them and readd them correctly, but they would display at the bottom, below even the internal item name.

I don't think this is that big of an issue, as it's still clearly understandable.