Essences inside ingredient bags display this text in the tooltip:

"This foul-smelling grime is the <rgb=#00BFFF>lesser magical essences</rgb> of evil-type item effects..."

Example is a lesser evil type essence, though all essences have the same display error.

Essence text displays correctly (e.g. without the <rgb> text and properly highlighted) when taken outside of the ingredient bag. Bug is repeatable when essence is returned to the ingredient bag.