In trying to delete specific tagged VLANs on switch trunk ports, I am receiving the message "Some tagged networks configured for the port do not exist" and the changes can not be saved.  The tagged networks clearly exist.  Has anyone else seen this problem?  What is the fix or workaround?

Update:  I just found a workaround.  When this issue occurs, 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.  The "Succeeded" message should now appear.