Cannot validate multi-valued attribute of primitive values

[ostrolucky]

According RFC 7643,section 2.4:

Multi-valued attributes contain a list of elements using the JSON
array format defined in Section 5 of [RFC7159]. Elements can be
either of the following:

o primitive values, or

Hence I would expect schema like this to work:

{
          "name": "tags",
          "type": "string",
          "mutability": "readWrite",
          "returned": "default",
          "uniqueness": "none",
          "required": false,
          "multiValued": true,
          "caseExact": false
}

However, validator crashes with that once validating with payload including"tags": ["Chewbag"]:

Type error: Tmilos\ScimSchema\Validator\SchemaValidator::validateByAttributes(): Argument #1 ($object) must be of type array, string given, called in /Users/gostrolucky/Documents/eqs/data-center-api/vendor/tmilos/scim-schema/src/Validator/SchemaValidator.php on line 86