PM891 only allowing single alarm and event subscription from PP885R touch panels

I have four PP885R touch panels communicating to a single AC00M PM891 controller. Only the most recently powered on panel is able to receive alarm and event status from PM891. I have adjusted the Parameter "AE Max number of event ubscriptions" from its default of one to five (four panels and one OPC server) with no change in behaviour.

Panel Builder 800 Version 6.2-0 Build 6.42.151.0
Control Builder M Prfessional, Version 6.1.0-0 Build 6.1.0.148