R700 alarming packets loss when Apple clients are connected to AP in 5G

[daniel_dedisse]

Hi, with my standalone R700 APs i'm able to always reproduce an alarming packet loss (10-15% with no other interference source) when Apple device are connected in 5G, tested with 9.8.2 and 100.1 firmware and iPhone6, iPad2, iPad Mini, Late 2012 MacMini.

My network usage is only a multicast video streaming server using (40% average AP airtime).

the step to reproduce are simple : 

connect 1 Windows Surface : i got 0,1% packet loss
connect 1 Androïd Surface : i got 0,1% packet loss
connect 1 Apple device : i got >10% packet loss on all connected device including Apple
disconnect Apple device : everything goes back to 0,1% normal

i suspect a broken compatibility mode gets enabled when Apple Device are present, or somehow Apple device are jamming signal ?! i'have monitored traffic with wireshark and i only see regular traffic (video packets) 

i'm not able to reproduce this bug on a 7982 AP

Please Help !

this is my config from factory defaults

set countrycode FR
set cwmode wlan8 0
set txpower wlan8 max
set directed-thr wlan8 0
set qos wlan8 directed multicast disable
set qos eth0 directed multicast disable
set qos eth1 directed multicast disable
set ofdm-only wlan8 enable
set 802.11-h wlan8 disable
set indoorblock wlan8 disable
set bss-minrate wlan8 24000
set ntp server 172.10.253.1
set txbf wlan8 disable
set roam_enable wlan8 disable
set ci wlan8 enable