The duplicate collection feature does not copy across the collection description or any metafields.
Hello! You're absolutely right; the "Duplicate Collection" feature did have a bug which prevented the copying of the collection description which we've recently addressed. Thanks very much for letting us know!
We appreciate your feedback as we're always looking for ways to improve the app. Please use the "Feature Request" button to share any additional thoughts.
Thanks for using Collection Manager and Happy Sorting!