Renaming a channel does not take effect in the Files section
If a channel are renamed from X to Y and you go into the Files section the the title that are shown is still X and not Y.
Yes, this is very frustrating and seems like a basic fix. We are struggling with this now as our organization is moving to teams. It appears that the only fix is to create a new channel if you care about folder structure.
Anthony Crain commented
I agree. This causes some folks confusion when they go into the files and see the old channel name. Also, I tried to rename the folders using sharepoint. The channel lost all of its files! I panicked for a minute, then renamed the folder back to the old channel name and all the files came back. This seems like it would be easy to fix.