My C-8 Pro arrived today. I am using the exact same UCTRONICS PoE Splitter that I was using on my C-8 hub, connected to my UniFi Lite 16 PoE switch. Once again, I have experienced no issues whatsoever with any of my Zigbee devices.
And, just to make sure... I paired a GE/Jasco Z-Wave switch as a quick test. I was able to pair it and control it with no issues whatsoever. Perhaps a Z-Wave mesh of just one node is not large enough for the issue to manifest itself? Or perhaps I am just lucky? Or perhaps the UniFi 16 Lite PoE switch is not one of the problematic ones?
I doubt it is an issue with total power output from the UniFi switches, as even their weakest PoE switches can easily handle 15 Watts. The Hubitat hub's average power usage is about 1.5 Watts. Even if we tripled that during radio transmit periods, we're still talking less than 5 Watts.
I 100% believe users have had this issue. I just caution against any blanket statements where Community members are told that a Ubiquitu UniFi PoE Switch + PoE splitter will not work with a C8 or C8 Pro hub.