OK, so it doesn't help too much but i have found this issue on the WAP571 with firmware 1.0.1.10
I was also finding major headaches with multiple wireless VLANs where the device would connect, get a DHCP address but no traffic flows, cannot even ping gateway of the VLAN
Rolled back to 1.0.1.9 and error went away.
blew out the seperate networks and recreated then everythign worked normally
This may help, but try rolling back one firmware level