I wanted to add more...I also have a very extensive setup and experience none of the problems you are describing. I have nearly 200 C4 devices (Keypads, dimmers and remotes), 4k video matrix (8 zone powering 10 end points) with a mixed device setup, theatre, 24 zone audio system, etc.Want to add my 2/100 of a dollar here.
We built a new home and had a $200K Control4 system installed. Absolute garbage. At best the system is unstable and unreliable needing constant reboots and "adjusting the matrix and baluns". At worst the system just fails to work.
I have to reboot the whole system at least once a week by powering everything off and then back on. The video distribution fails to work more often than it works. The tech has been out at least 20 times and it failed again yesterday.
The lighting control will randomly lock up requiring all the dimmer packs to be rebooted by turning off the breakers and then back on.
The "comfort" (thermostats) has worked correctly for a total of about three days. Every time the tech resets it it works for a few hours and then fails again. We can see the temperatures of the zones but can't set anything.
The intercom is a joke with so much lag that trying to have a conversation is more difficult than a tech support call to Mumbai. The security cameras only update every twenty seconds.
The only thing that works remotely reliably is the audio distribution.
If you are interested the system was installed by Audio-Video Experience out of Hampton Falls, NH.
From the what you describe if you are having issues with the video distribution and the baluns there is something wrong with the wiring or they specced the wrong baluns for your end points.
As far as the other issues I'm wondering if you do have network issues. I assume that you intercoms are hard wired. If not, they should be. My dealer said they will never (unless the client insists) run them over wifi due to potential lag. When we installed our door stations and in-wall keypads it was a PITA for them to get the wiring in-place but they did it.
With that said...what you are experiencing would be SUPER frustrating but it is not my experience with C4 at all.