foundry.js:753 TypeError: Failed data preparation for Actor.. Cannot read properties of undefined (reading 'ac')
at Actor5e._prepareBaseArmorClass (actor.mjs:281:39)
at Actor5e.prepareBaseData (actor.mjs:111:10)
at Actor5e.prepareData (foundry.js:14032:12)
at Actor5e.prepareData (actor.mjs:95:11)
at Actor5e._safePrepareData (foundry.js:14010:14)
at Actor5e._initialize (foundry.js:13838:19)
at new DataModel (commons.js:6776:12)
at new Document (commons.js:7438:3)
at new BaseActor (commons.js:9138:3)
at new ClientDocumentMixin (foundry.js:13802:7)