Sorry, this is a bit of an odd one, I will try to fully explain what happened.
I have 4 Apple TVs as clients. I have no specific settings for individual clients - they all take their settings directly from the Server. All are Apple TV 4K tvOS on 18.1 running Channels v6.3.0.
I have 2 main sources both with custom M3U setups - One Satellite and one Terrestrial.
This setup has been running faultlessly for 6 months or more.
Yesterday, I was adding a test source of a single channel for experimenting with recording from a LinkPi. I did not add that source to the clients' list and have since deleted it anyway, so this may be completely unconnected with the issue, but for complete disclosure I mention it.
Anyway, last evening, I noticed that on my Lounge client (which was the only client active when I was adding the test source) the guide now had missing logos for some channels. The missing ones were for channels where I have 2 sources for the same channel - terrestrial and satellite.
Although I thought it was odd that only one client was affected, I disabled the terrestrial source as that is only there as backup anyway. So there are now no duplicate channels, but the logos were still missing.
So I have now tried:
Disabling the main satellite source and then re-enabling it.
Refreshed the guide data for the source.
Rebooting the relevant Apple TV.
Unplugging the Apple TV and restarting.
All the above still resulted in the same missing logos.
So on the affected client, I uninstalled the Channels app with the "remove data" nuclear option and then reinstalled it.
That at least made a difference - now I have no logos at all!
My logos are all defined in the Custom source m3U file directly and locally hosted. I have triple checked that the logos are available on the network. And as I said, all other clients display all the logos.
I am now running out of ideas. I have now only the single active source which I have just refreshed the guide data on and I still no logos in the guide for the one Client, while the others are fine.
Throughout all of the this the Server Side guide has logos for all channels.
Any ideas?
Edit Just to add if I look at the source on that Client under settings / manage sources the channel list there has logos showing. But they still don't show in the Guide.