I did a report there Basic-Shields. Your mod is allowing to dupe the shields when spamming left click in enchanting table

Yeah that's on me, Basic Shields has nothing to do with it. Problem is with shields in general, basically any item that is unstackable, but cannot receive enchantments at the enchanting table.

Fixed now as of v1.0.4 (1.16) and v2.0.1 (1.17).