quid is 0 in all records in question_node table

When inserting new row in the question_node table, question_validate function works fine, and $node->quid is correct. But something happens after that, before query_insert call. In query_insert $node->quid is already empty, and correspondingly 0 comes to quid field in the question_node table.

I used a workaround - just reassigned $node->quid in question_insert in the same way as it is done in question_validate.