Mandatory Select field in form: no error message if nothing is selected

I got this Select item in a form:


Clicking on Submit doesn’t display an error message for the Select field; it works fine for other mandatory fields. I also added a Modal element and the workflow correctly uses the false branch:

But the modal is not displayed either (might be another issue although I don’t find any reason why).

I recently had a similar issue but I couldn’t always reproduce it so I closed it:

There is also this older issue:

The Select item has a Required property in the meantime but it still doesn’t work. It only works, if I select a country, remove it
image
and then click Submit again:
image

But this is not something the user usually does. This is probably a bug.