WAX218 Radius accounting messages have 0 for a client traffic

Hi,

Could somebody help me to understand why I am getting "0" in radius accounting messages for traffic.

All these tags have "0" as value:

42 Acct-Input-Octets
43 Acct-Output-Octets
47 Acct-Input-Packets
48 Acct-Output-Packets
52 Acct-Input-Gigawords
53 Acct-Output-Gigawords

Interesting that the

77 Connect-Info 

has some weird text that doesn't reflect connection speed at all: "CONNECT 0Mbps 802.11a"

There are 4 AP with the same issue so far. Firmware Version:2.1.1.3