Steps to reproduce the issue

In backend menus, click "new" and get the edit screen for a menu item.

Enter a name, set different values in the right column,
i.e. set state to trashed, enter a note, select an eccess-level.

Then activate the "select menu type" button, choose a Menutype and close the modal.

Expected result

The input made in the right panel is as before.

Actual result

Most inputfields in the right panel are reset to the default values of the respective FormFields

System information (as much as possible)

Additional comments

3.8.12, but maybe this exists since a longer time.
I got it first some weeks ago, with 3.8.11.