Used a Sharp 5 Netherite sword on a Vindicator wearing a full set of Protection 4 + Thorns 3 netherite armor. I was wearing the same armor, as the vindicator, If a video of proof of how it exactly occurred is required, I got it. It crashes as soon as I sword-crit the vindicator, and when you join back into the world, the entire inventory you were carrying disappears. I'd have to guess it's the change to the damage reduction.