Looking at call ID 646187c57298733bf97aada80076f60f@141.31.8.62, which is the Interview Item Ext 3333, it turns out that there are only entries in openvxmllogs after the fourth question:
select * from openvxmllogs where sessionId = '91307d20-8549-487c-83a0-2a3d8f847de0';
The reason is that the current call flow does have four inconsequential questions at the beginning of the call flow with no script block following. We will have to identify a method to log every variable going forward.