Channel names agree on every Mac
When two admins rename a channel, the later name wins. Two channels made with one name at the same moment now read apart, as name and name-2.
If two admins renamed the same channel around the same time, the name that stuck depended on which Mac it came from, not which change was newer. Now the later rename wins, on every Mac.
Two admins could also each make a channel with the same name before hearing about the other, leaving two channels you could not tell apart. One keeps the name and the other shows as the same name with -2, the same way for everyone.