Anyone know why I'm encountering this error with farapp (NS Connector) when trying to add/update a matrix item "Mapping errors: Errors adding variant metafields: {'code': 'INVALID_VALUE', 'elementIndex': None, 'field': ['metafields', '0', 'value'], 'message': "Value is invalid JSON: unexpected character: 'All' at line 1 columns 1."}