If you select another entity in a RefGUIDList tagged value with the same name as the previous entity then the new value is not saved.
Steps to Reproduce:
Create RefGUIDList tagged value that references attributes like this
Type=RefGUIDList;
Values=Attribute;
AppliesTo=Attribute;
Add this tagged value to an attribute.
Select an attribute with name "A"
Select something else
Now select the same attribute again and select a different attribute with name "A"
Select something else
Go back to the attribute with the tagged value
Notice that the tagged value still references the first attribute with name "A"
Reported
Geert