Mods like Advanced Netherite or Warden Loot has custom chestplates, but the enchantment does not work.

Yes please

Does testing Sonic Deflect without warden loot in my environment help? If so I'll do it after work.

Thank you for replay.

As you can see, I also use warden loot.

Me too. Does pasting mods list I installed help?

hmm, I tried some more testing and I couldn't repeat the bug

I tested with the Warden Loot (my mod) chestplate and the vanilla diamond chestplate, and both of them sometimes worked and sometimes didn't. I couldn't figure out what was making them work or not work, but I don't think that the issue is with modded chestplates (unless there is a separate issue)

Interesting. There is no specific way to trigger the bug?

I tested sonic deflect enchanted diamond chest plate with/without warden loot mod and sonic deflect enchant doesn't work in both cases.

I disabled every mod except for Sonic Deflect and fabric API and it doesn't work.

still not working lol