Right-clicking any piece of armor present in an armor slot, in survival, duplicates the item into an open slot in the player's inventory.

Forge: 35.1.0
ARL: 1.6-47
Quark: r2.4-278

Latest log file

ffs I knew I forgot an edge case lmao

The same happens in Quark-r2.4-279 when right-clicking an armor inside a chest or on a repaired armor through the anvil/inventory/crafting table (removing the first slot item).
Forge: 35.1.3
ARL: 1.6-47
Quark: r2.4-279
latest.log

This is still happening in r2.4-280 for me.
Forge 34.1.42
ARL 1.6-47
Quark r2.4-280 (tested in 282 as well)

Latest Log

Of note, I'm using this modpack: https://www.curseforge.com/minecraft/modpacks/masonsmodpack