for tag in tag_groups:
tag_db_name = self.mapper.tag_column + "_" + strip_prefix(tag, TAG_PREFIX)
group_data = self.parameters.get_group_by(tag)
if group_data:
tag = quote_plus(tag, safe=URL_ENCODED_SAFE)
group_pos = self.parameters.url_data.index(tag)

quote_plus above is failing because the tag has a white space and we are using the wrong conversion here.