The field found here: /modules/standard-templating-kit/dialogs/components/teasers/stkTeaserContact/form/tabs/tabTeaser/fields/contact/contentPreviewDefinition has a contentPreviewDefinition property which points to info.magnolia.contacts.app.field.component.ContactPreviewComponent. If you do not have the contacts module installed this creates a CNF issue. However the stk module does not have a dependency on the contacts module that would prevent the CNF issue from occurring. Or another approach may be that the stkTeaserContact template and dialog should actually be a part of the contacts module.