When the viewpoint of a person is in 3rd person, with the camera inside a banner, and pointed at enchanted armor or weaponry, the enchantment glint can be seen through the texture of the banner. This only works if the camera is INSIDE the banner. Other visual glitches also occur, like when looking at a frozen lake from this viewpoint. The type of banner does not seem to matter, I found it with both pillager banners and black banners. turn enchantment glint and speed all the way up for easiest viewing, but it does not depend on that as long as they are on.