Vantage 410 & BAQs

We recently upgraded our Vantage system from 803 to 410 and have begun seeing some strange behaviour in BAQ. Specifically, a BAQ which previously displayed information on unfirm jobs now picks up nothing, when there most definitely are unfirm jobs to display. By way of trouble shooting I set up a BAQ with one table - jobhead, and one field, jobnum, no criteria, but still nothing shows up

HAs anyone else had this issue before and how was it resolved ?