Decided to experiment with the new amulet. Rerolled it several times, and equipped it once without incident. Then rolled "+1 Imbuement, +1 to existing Imbuement". It was the first time I'd gotten an enchantment, and didn't know what Imbuement was (still don't even know what mod it's from).
The world crashed, and I can't reopen it because I'm still wearing the amulet.
I also don't know what sort of equipment the Imbuement effect would have been added to... I was wearing no armor, and carrying only a modded pick and bow. Nothing else enchantable.
https://pastebin.com/7ySJNSgV

Managed to replicate the crash.
I believe Imbuement is from Electroblob's Wizardry, as that mod has enchantments like "Fire Imbuement" and "Frost Imbuement" that can be temporarily added by spells. Imbuement itself is likely the non-elemental version.
Also involved is Thermal Expansion and Redstone Arsenal, as the crash did not occur until I was carrying some of RSA's fluxed weapons/tools.
It may be that the crash has nothing to do with Astral Sorcery at all, and is just a result of an Electroblob enchantment being applied to an RSA tool. Will continue testing.

Edit: Applying Imbuement normally, via the Electroblob spell, causes no issue. Equipping a Prism with "+X to existing Imbuement" does not increase the level of the Imbuement enchantment, whether equipped before or after the spell is cast. Equipping a Prism with "+X to Imbuement" does not apply the Imbuement enchant to any items that could otherwise accept it. It does, however, immediately crash the game when Redstone Arsenal's Flux Bow and Axe are present.
This is a very strange cross-mod interaction.