The detail content isn't copied to the clipboard. When pasting, it loads from the source DB via the item IDs on the clipboard (UltraRecall:Items, UltraRecall:Filename formats, etc.).
So that tool seems to have some issues. This one worked better for me.
https://www.nirsoft.net/utils/inside_clipboard.html
You can check
Options | Refresh on Clipboard Change to dynamically update.
I would need to be able to reproduce the behavior you're seeing in order to investigate. You might try starting Windows in Safe Mode to rule out any interfering applications.
https://www.kinook.com/Forum/showthread.php?t=4041