Just to remind you, I reported a dupe glitch on github a few days ago, hope you can fix it.

Works perfectly fine, even had a dude try and dupe and he has not managed to lol

Works great on 1.20.2! Was so glad to see this plugin- on big servers it's such a pain not being able to access your shulkers in public areas or at another player's base, so I knew I wanted this for my server. It's a little tweak with a big impact for players! LOVE IT!