Hello. I've installed FOP2 2.29.01 in FreePBX Distro (asterisk 13.40, freepbx 12.0.70).
I've checked that it work properly and send a link to our operators (about 15 clients).
When all of these login to fop2, fop2 stop tu update buttons, some buttons updates, some does not.
For example, I can login to Fop2 and make a call, Fop2 doesn't show it. If I relod fop2, fop2 shos buttons corretly, but hase a problem with updates.
If only 1-4 clients are connected, fop2 works properly, but not always. Very often fop2 show orange button, when operator (queue member) stop to talking or transfer a call. Fop2 shows orange button and shows all lines is free.

Contents of my /etc/asterisk/manager_custom.conf

[fop2]
secret = fop2pass
deny = 0.0.0.0/0.0.0.0
permit = 127.0.0.1/255.255.255.0
read = all
write = all
writetimeout = 1000
eventfilter=!Event: RTCP*
eventfilter=!Event: VarSet
eventfilter=!Event: Cdr
eventfilter=!Event: DTMF
eventfilter=!Event: AGIExec
eventfilter=!Event: ExtensionStatus
eventfilter=!Event: ChannelUpdate
eventfilter=!Event: ChallengeSent
eventfilter=!Event: SuccessfulAuth

Screenshot of orange button with free lines (extension 2001) in attach.
Second screenshot - button is green, lines it inactive, but icons of lines shows incoming call