Hello!
I've been playing the mod for some time, and I recently discovered that when using the Ars Nouveau/Elemental modifiers (Novice, Mage, etc.) on armor pieces, they gain Mana Boost and Regen enchantments. However, if you enchant those pieces with another mod (like Ars Nouveau itself for example, with the Reactive enchantment or any other), the new enchantments are removed when you hold or wear the armor.

Additionally, if you use a disenchanter table, you can transfer the Mana Boost/Regen enchantments to books but they will return to the armor afterward, essentially creating an infinite source.

Moreover, when upgrading to any of the Elemental sets (Aethermancer, Pyromancer, etc.), the armor retains all benefits from other sets.

I would like to know if this is intentional.

All of this was tested in Minecraft versions 1.19.2 and 1.20.1.

On top of that @wendall911 it seems like if you already have a modifier (Novice, Mage, etc.) to upgrade to a higher tier it costs an upgrade slot, is this intentional?

Yes, this is how it has to work due to changes in Tinkers' Construct. They removed the ability to have upgrades with dependencies. If they ever bring that ability back, I'll change it to have a requirement. This is intentional for now. I think the limit in the number of upgrades is an OK balance. Not exactly what I intended, but it will have to work for now.