I have begun to use switch port labels for grouping ports.  I have run into the same issue that I mentioned in a post a week ago in which I receive the message "Some tagged networks configured for the port do not exist".  This randomly occurs when creating a new label for a port or when trying to assign an existing label to a port.  The solution is the same workaround mentioned in my prior post which is to select "Allow All" for the Network Tags Setting and click Apply.  Then edit the setting again and select "Custom", delete the entries you don't want, and click Apply again.

It is a minor issue but it needs to be addressed and corrected.