More assumptions, and correct where necessary.
You identified the switch as rack mounted, but is this a 100% Avigilon branded Dell OEM Rack Mount Server Model # beginning with storage size and ending in HD-NVR2?
If so, these systems use W7embedded, and Avgilon maintains the latest tested drivers, firmware, etc, all that apply via a bootable USB onto the Dell Lifecycle Controller.
Or is this a Tower OEM Avigilon NVR.
You have joined these servers to you AD?
Are they is a seperate OU - completely isolated from GP's
Do you use a network management system? IE, something that is pinging devices, or using sythentic ICMP packets to determine health?
Earlier you said power loss, how is this being allowed to happen? Bad or NO UPS's on switches or servers? (Not a healthy things)
regardless of all answers, assuming the physical layer is sound, then moving up to to L2, check out ARP packets...
https://ask.wireshark.org/questions/7277/arp-broadcast
I would suggest you create a trace of a camera that correctly reconnects, on 1 or more VLANs, then run a real-time filter capturing future arp traffic.