[OBD U5] unhide copy/hidden cached elements

In OBD U5, BuildingTemplate_AU

Referencing this help page:

https://docs.bentley.com/LiveContent/web/Designer%20Help-v1/en/GUID-6160BBE5-7D84-EAA1-BFDE-26521D10DE47.html

"Selecting Copy/Hide Cached Element copies the element or selection set into the master file and hides the cached element or selection set. You can manipulate the copied elements. Deleting these elements will display the hidden cached elements."

Deleting copied elements doesn't un-hide cached elements. Is that WAD or is that a defect? Or am I understanding the bolded sentence wrongly? SR 7000931106 raised.

Best regards,

Tuan Le