Its more of a suggestion than an issue. I have a mod that allows Horse Armor to be enchanted, when I combine an Enchanted Horse Armor with a rune, and put that Armor on horse, it does vanilla Enchantment Glint

The screenshot has Enchanted Iron Horse Armor + Lime Rune

The mod that allows Horse Armor to be enchanted: https://www.curseforge.com/minecraft/mc-mods/universal-enchants-forge

This would need to be implemented by that mod, as by default there's no shining on it for quark to hook onto