Sounds like you may have bigger issues than the camera names.
I know you can go into the camera's web GUI and update the name there too...maybe there is a conflict and the NVR is not pushing the update correctly to the cameras?
I know a lot of folks here advise to make any changes for the cameras on the web GUI of the camera itself, with Internet Explorer.
I have a new Dahua NVR I will be setting up this weekend and swapping a tempt rebranded NVR with it.
I have a spare lower quality camera...before I start putting the permanent config on my NVR, I will do some testing.
I know the name update between the NVR GUI and camera GUI itself seem quite different.
I will report back what I find.
Just wanted let you know that I have done extensive experimentation with this issue. I have changed camera names from the web GUI of the cameras themselves, web GUI of NVR as well as the NVR GUI itself. All result in same issue. Camera names change to “channel x”, “channel xx,” etc. which tells me that the NVR is assigning these names because when a camera defaults, it defaults to “IPC”
ps. I reboot once per week because I find that for some reason it helps maintain the time more accurately.