Confirmed! Same problem in 4.1.1-rc1
It's a bug.

confirmed

Yes, I am also able to reproduce it. can anyone guide me on what to do to solve this issue?

I think the error happens here: https://github.com/joomla/joomla-cms/blob/4.1-dev/administrator/components/com_menus/src/Model/ItemModel.php#L1429

$pk is detected wrongly:
$pk = (!empty($data['id'])) ? $data['id'] : (int) $this->getState('item.id');

Background:

• The controller sets $data['id'] explicitly to 0 if we're in a save2copy task.
• Therefore $data['id'] is detected as empty in the model and $pk falls back to $this->getState('item.id') which is the id of the menu item to be copied.

Maybe solution:
$pk = (!empty($data['id']) || $data['id'] === 0) ? $data['id'] : (int) $this->getState('item.id');

Maybe solution:

Not tested enough, but it seems to fix the issue for me.

@anmode
If you want: Do you like to provide a pr with my solution (or a better one if you think so)?

@ReLater I'll test your solution. If it works fine than awesome. I would like to send pr with your solution and i I'll also try to add something.

yeah! Fantastic this working correctly. I have tested it. could i generate a pr for it?

could i generate a pr for it?

Everybody is allowed to provide a pr for Joomla without asking before. You, too ;-)
It will be reviewed and tested then by others. You can make changes if needed.

could i generate a pr for it?

Everybody is allowed to provide a pr for Joomla without asking before. You, too ;-) It will be reviewed and tested then by others. You can make changes if needed.

okay sure! Thanks for the solution btw :).

Closing as we have a PR #37395