FWF 60D V5.2.4 - wifi not working with MAC

I have a site I setup with a FWF 60d, and 3 X FAP-220B (all latest FW).

PCs seem to be fine, phone and Ipads seem fine, but MacBook airs (I think they are all airs) - they show full signal, have an IP address, but can do anything.  the FG show as the DHCP is issued, but the wifi client list does not list the unit.  It is very weird.

Turning Wifi on / off, helps once in a while.  Rebooting does seem to fix it.

About 60 clients max on the network.

Any ideas on what to do / look / change?  I'm at a loss, never seen anything like this.