The bug

When you click in any inventory slot, empty or filled, the enchanting overlay on all visible items seems to "snap" to a new, seemingly random frame. This does not seem to happen in the regular inventory interface, or various UIs I tested such as anvils, enchant tables, droppers, etc. It affects chests and barrels.

How to reproduce

Open a chest with some enchanted items in your inventory. Repeatedly click an empty slot and watch the enchantment overlay.

Attachment

A video demonstration of this behavior is attached: ench.mp4