I've faced the following error:
vue.common.js:1019 [Vue warn]: Error when evaluating expression "filteredOptions.length === 0 && search.length": TypeError: Cannot read property 'length' of undefined (found in component: <multiselect>)
Changing v-show="filteredOptions.length === 0 && search && search.length" to v-show="filteredOptions.length === 0 && search && search.length" seems could fix it.
For now I just override the template.