FP231G Dual 5g: clients only connecting to radio 2

[John1028]

I'm having an issue with Dual 5g mode on my FP231G APs.

Radio 1 is off

Radio 2 is the low 5g channels

Radio 3 is the high 5g channels

Dense deployment (it's a school and every classroom has an AP)

The issue is all clients are only connecting to radio 2.  Radio 3 is propagating, I can see it with the fluke WIFI scanner.  DAARP is working, the client experience is pretty good except I'm getting some very high channel utilization numbers due to the fact that the clients are all connected to just 4 channels on radio 2.

I made a new connection profile with single radio 5g and that's working great, all the channels are utilized and my channel utilization issues are gone or very minimal.

I made a test profile with dual 5g enabled, radios 1 and 2 off, and clients connect to radio 3 without a problem.

My questions are:

• Is there a way in the config to encourage clients to connect to radio 3 when using dual 5g mode? 
• Is this likely just a client issue and they are choosing the lower frequencies for reasons I can't do anything about?
• Do I have something goofy in my config that is preventing radio 3 from being used?

Thank you!

config radio-2
set band 802.11ax-5G
set band-5g-type 5g-low
set channel-bonding 40MHz
set power-mode dBm
set power-value 7
set wids-profile "default"
set darrp enable
set arrp-profile "arrp-default"
set vap-all manual
set vaps xxxxx
set channel "36" "44" "52" "60"
end
config radio-3
set band 802.11ax-5G
set band-5g-type 5g-high
set channel-bonding 40MHz
set power-mode dBm
set power-value 7
set wids-profile "default"
set darrp enable
set arrp-profile "arrp-default"
set vap-all manual
set vaps xxxx

set channel "100" "108" "116" "124" "132" "140" "157"