Error in harvesting/deleting if bbox not set

[etj]

2013-09-11 14:16:17,248 ERROR [ckanext.harvest.harvesters.base] Invalid package with GUID facec6d9-4a1e-46b8-b761-a66b36d1199f: {'spatial': [u'Error decoding JSON object: Expecting object: line 1 column 35 (char 35)']}
2013-09-11 14:16:17,248 INFO  [ckanext.harvest.queue] Received harvest object id: 8fa390cb-ae04-4687-ac92-5a62941b79d8
2013-09-11 14:16:17,252 DEBUG [ckanext.harvest.harvesters.ckanharvester] In CKANHarvester fetch_stage
2013-09-11 14:16:17,253 DEBUG [ckanext.harvest.harvesters.ckanharvester] Using config: {u'default_tags': [u'provincia-firenze'], u'force_all': True, u'default_extras': {u'harvest_url': u'{harvest_source_url}/dataset/{dataset_id}', u'nodo_origine_cerco': u'Provincia di Firenze'}}
2013-09-11 14:16:17,353 DEBUG [ckanext.harvest.harvesters.ckanharvester] In CKANHarvester import_stage
2013-09-11 14:16:17,354 DEBUG [ckanext.harvest.harvesters.ckanharvester] Using config: {u'default_tags': [u'provincia-firenze'], u'force_all': True, u'default_extras': {u'harvest_url': u'{harvest_source_url}/dataset/{dataset_id}', u'nodo_origine_cerco': u'Provincia di Firenze'}}
2013-09-11 14:16:17,404 INFO  [ckanext.harvest.harvesters.base] Package with GUID fc3b9215-0681-4881-a168-dd2b186e60d6 exists and needs to be updated
2013-09-11 14:16:17,481 DEBUG [ckanext.spatial.plugin] Received: u'{"type":"Polygon","coordinates":[[[, ],[, ], [, ], [, ], [, ]]]}'
2013-09-11 14:16:17,482 ERROR [ckanext.harvest.harvesters.base] {'Spatial': u'Error decoding JSON object: Expecting object: line 1 column 35 (char 35)'}
Traceback (most recent call last):
  File "/home/ckan/pyenv/src/ckanext-harvest/ckanext/harvest/harvesters/base.py", line 152, in _create_or_update_package
    new_package = get_action('package_update_rest')(context, package_dict)
  File "/home/ckan/pyenv/src/ckan/ckan/logic/action/update.py", line 752, in package_update_rest
    dictized_after = _get_action('package_update')(context, dictized_package)
  File "/home/ckan/pyenv/src/ckan/ckan/logic/action/update.py", line 273, in package_update
    item.edit(pkg)
  File "/home/ckan/pyenv/src/ckanext-spatial/ckanext/spatial/plugin.py", line 65, in edit
    self.check_spatial_extra(package)
  File "/home/ckan/pyenv/src/ckanext-spatial/ckanext/spatial/plugin.py", line 85, in check_spatial_extra
    raise ValidationError(error_dict, error_summary=package_error_summary(error_dict))
ValidationError: {'Spatial': u'Error decoding JSON object: Expecting object: line 1 column 35 (char 35)'}
2013-09-11 14:16:17,490 ERROR [ckanext.harvest.harvesters.base] Invalid package with GUID fc3b9215-0681-4881-a168-dd2b186e60d6: {'spatial': [u'Error decoding JSON object: Expecting object: line 1 column 35 (char 35)']}