PerCon ID Not Saved to QuoteCnt Table Consistently

We have noticed that the PerConID is not consistently written to erp.QuoteCnt. If you lookup by name in erp.PerCon the contact is there with a PerConID. Anyone else seeing this? We are trying to pull back contact information on quotes using the PerConID but it’s not always in the table. I don’t see another way that the erp.QuoteCnt and erp.PerCon tables are linked.