On a system with Asterisk 13.9.1, FreePBX 12 and FOP2 2.30.02, we have a problem whith incoming calls to queues. When a call enters a queue, the small icons of the agents of the queue start moving indicating the extensions are ringing, but the extension buttons do not turn orange for 10 seconds or more (seems some sort of delay).
All the agents of the queues are dynamic. We have 12 queues with 8-12 dynamic agents in each queue, and 44 extensions in the panel.
We have tried FOP2 2.31.00 and 2.31.01, with the same results (but had to revert to 2.30.02 because some bug made some calls appear empty in the queues boxes and would not disappear).

Can it be caused by too many AMI events? Is there something we can do?

I forgot to mention Eventfilters in manager.conf didn't seem to make any difference

After looking at the problem a bit more, we've seen that the delay happens when there's more of 2 "free" agents in a queue. And it seems exponential: more free agents, more time it will take to show the ringing status of the extensions (even if we hang up the call, the call will appear and then disappear).

Don't know if it's relevant, but looking at the fop2 log, when the call enters the queue, we can see the RINGING (output with a few greps to only show relevant data):

127.0.0.1 <- Device: Queue:127
127.0.0.1 <- State: RINGING
--
127.0.0.1 <- Privilege: call,all
127.0.0.1 <- Device: SIP/350
127.0.0.1 <- State: RINGING
--
127.0.0.1 <- Privilege: call,all
127.0.0.1 <- Device: SIP/351
127.0.0.1 <- State: RINGING
--
127.0.0.1 <- Privilege: call,all
127.0.0.1 <- Device: SIP/352
127.0.0.1 <- State: RINGING
....

But until we see the ChannelStateDesc: Ringing, the buttons do not appear as ringing. Don't really know if it could be a clue.