If saddle is enchanted and a horse has unenchanted horse armor the horse armor gets the enchanted glint on some parts. The lower leg armor parts do not get glint, but the parts where the saddle is near do. It happens on the body and near the head.
Note: if done the other way around (where there is enchanted horse armor but not enchanted saddle) does not produce the result.
Steps to Reproduce:
Run the following command
/summon minecraft:horse ~ ~ ~ {Tame:1b,equipment:{saddle:{id:"minecraft:saddle",components:{"minecraft:enchantment_glint_override":1b}}, body:{id:"minecraft:diamond_horse_armor"}}}
❌ Part of the horse armor has the enchantment glint
I am able to reproduce the reported behavior. It has been present since 25w03a; previously, neither the saddle nor the horse armor would have a glint when the saddle was enchanted.