If you bind an IP adress to a Mac address, then the 2820 uses this information for ARP resolution, I don't think it should.
For example you have a printer plugged into a wifi client eg. Netgear WG602v3 or similar, and you bind the printer's IP address to it's Mac in the 2820 so that the printer always gets the same IP address from DHCP. This now means the the 2820 tries to use the printers Mac address to talk to the printer rather than the wifi clients Mac address, this doesn't work. This means that the printer cannot access the internet or other networks linked by VPN. I have the same issue with my Samsung television which connects is a similar way & so this could not access BBC iplayer or other internet services.
This issue has come up after replacing my Netgear router with the Draytek, the Netgear router (supplied by SKY) obviously handles things correctly.
I can work around this by using a static IP setup, but this is inconvenient. My tv doesn't need a static IP, but my printer does.

Sounds like the same problem I get with my 2920 and 2960.

The setup I've got is two tv's and media player and networked TV recorder these are connected to two buffalo wireless ethernet bridges. If I enable strict bind or bind the devices can browse the local lan but not the internet. It also causes an ip conflict with the bridge. My solution was to set fixed ip address's on the TV and media boxes so they didn't request an ip. This way I get full access on the lan and they can access the internet.