When looking at some custom data classes, rather than seeing the actual data class name in the tree view, the GUID is seen as the Name. However, the Name is actually there in the actual main panel and also when clicking on that data class it shows the Name but goes back to the GUID if browsing away and then it comes back.
Note: Another user case for this issue is when creating a new custom inventory and first clicking on the data it shows it as the GUID and then updates to the Name.
ITMS 8.5, 8.6
The User that created these custom data classes in the past belonged to a custom security roles (they have cloned Symantec Administrators).