Hi @sprucelydesigned,
we’re sorry for the problem you are experiencing. The upgrade notice is designed (since it was introduced years ago) to stay dismissed but some bugs can occur when the AJAX call fires (e.g. another plugin or a PHP warning output breaking the response, etc.) so there is as a failsafe way to overcome this.
You can visit Settings → Duplicate Post, third tab “Display”, and then untick “Show upgrade notice” and save the settings. This will prevent the notice to be displayed again.
Let us know if this works!
Please also note that we are phasing out the notice to replace it with a more efficient way to inform users about the new features so it will be probably removed in a future version.