Redmine

When selecting a category, the default assignee of that category should be shown automatically.

This feature works correctly in Redmine 5.1.2.
However, after upgrading to Redmine 6.1.1, it no longer works.
The assignee is actually selected, but it is not shown correctly in the UI.

We found the difference in the HTML of the assignee field.
In Redmine 5.1.2, the HTML is:

<select name="issue[assigned_to_id]" id="issue_assigned_to_id">
  <option value="">user2 test</option>
  <option value="1">&lt;&lt; me &gt;&gt;</option>
  <option value="1">Redmine Admin</option>
  <option value="5">user1 test</option>
  <option value="6">user2 test</option>
</select>

In Redmine 6.1.1, the HTML becomes:

<select name="issue[assigned_to_id]" id="issue_assigned_to_id">
  <option value="" label=" ">user2 test</option>
  <option value="1">&lt;&lt; me &gt;&gt;</option>
  <option value="1">Redmine Admin</option>
  <option value="5">user1 test</option>
  <option value="6">user2 test</option>
</select>

There is a new attribute label in the first <option>:

<option value="" label=" "></option>

According to the HTML specification, if an <option> has a label attribute, the browser will display the label value instead of the inner text.
Because the label is " " (empty space), the selected assignee appears blank in the UI, even though the value is set.

We suspect this change may be related to the new UI/theme in Redmine 6.x, but we are not sure where it should be fixed.
Could someone help check and fix this issue?