The bug

When hovering over enchanted items, the tooltip is slightly transparent. However, that is not the case with enchanted items in a villager's trade GUI. Instead, the tooltip is opaque.

Steps to Reproduce:

• Summon a villager with trades.

• /summon minecraft:villager ~ ~ ~ {NoAI:1b,Offers:{Recipes:[{buy:{id:"minecraft:emerald",Count:1b},sell:{id:"minecraft:iron_axe",Count:1b,maxUses:9999999}}]}}

• Hold your mouse cursor over the iron axe.
• Look closely at the opacity of the tooltip that's displayed upon doing so.
• Take note as to whether or not tooltips within the villager UI are opaque.