I updated to 6.3.1 and checked, the problem remains. In the official version of ETS 631 it is not possible to paste unregistered devices into the project. The feature is unlocked only with special developer or tester licenses. Perhaps you have one of these licenses or a modified version of ETS, but I haven't seen one yet. Try logging out of ETS, go to demo mode and copy paste unregistered device, you will probably see the same error as in the screenshot.
What can I say... You can see the screenshot I attached, right? There you can see the message that ETS shows when trying to insert an unregistered device into the project. The functionality of the program cannot be different for different users in the same official version, because the Association itself explained that in ETS versions "ETS 6.3.0 and above" the copy function will be blocked for unregistered devices.
Sie müssen registriert sein, um Links zu sehen.
1. The import function of projects with unregistered devices is not blocked.
2. Only inserting unregistered devices into the project is blocked.
3. Inserting unregistered devices into a project in official version 630 and higher can be unlocked only if you have a developer or tester license.
4 The above described blocking of functionality was introduced by KNX association intentionally, the link to the information from the official source was in my previous posts.
Unfortunately I have no idea what you have going on in your ETS.
If you could share the ETS631 with the unlocked functionality of inserting unregistered devices, I would be very grateful. As probably many in the KNX community))