Sorry, didn't see it. I guess you can delete it now.
Thanks both of you for explaining, I didn't have the chance to test it on a vanilla server at the time of reporting, but I did that now and it seems to work actually. I'm using Spigot, so I think it has some sort of invalid enchant filter in place server-side to stop us from sending invalid enchants to the client. I don't know why though. Anyways, I'll report this issue to them then. Thanks anyways for your support and sorry for being so sour with you.
Just marking an issue as "Works as intended" won't solve anything. Also, "Works as intended" is actually a lie. I'm rather sure the Mojang developers didn't just wake up one day and choose to remove a feature for the sake of annoying the community, and then saying "It's not a bug, it's a feature!".
Did you even try that? It won't add the glint at all. Besides, I have already tried adding invalid enchants or invalid levels.
Any updates on this?