It happens immediately after I click OK on the form. (The form opens the report, which runs the query.) I'm also posting the SQL of the query called 'qryAnomaly' as you suggested:
PARAMETERS [Forms]![frmAnomaly]![cboAnomaly] Value;
SELECT tblMainDataTable.ID, tblMainDataTable.[Tag #], tblMainDataTable.Name, tblMainDataTable.Date, tblMainDataTable.Team, tblMainDataTable.Machine, tblMainDataTable.[Anomaly Observed], tblMainDataTable.[Anomaly Description], tblMainDataTable.[Corrective Action], tblMainDataTable.[On], tblMainDataTable.Countermeasure, tblMainDataTable.[Assigned to:], tblMainDataTable.[Closed?]
FROM tblMainDataTable
WHERE (((tblMainDataTable.[Anomaly Observed])=[Forms]![frmAnomaly]![cboAnomaly]) AND ((tblMainDataTable.[Closed?])=No));