Validation message in the right side panel cannot count errors correctly

Scenario:

1. Add to one of the fields required validator and for the another 'non-empty' validation.
2. Open the document in the visual editor.
3. Make field with non-empty validator required.
4. Press save.
5. Make the required field empty.

Problem: validation message says "Document has 1 error" but in fact, panel shows two errors.

Expected: no number for errors count is shown at all.