Typed property Drupal\Core\Form\ConfigFormBase::$typedConfigManager must not be accessed before initialization
Problem/Motivation
Setting up a new site using Core 10.2, Devel 5x. The Devel settings page, on 'save' produces the following:
Error: Typed property Drupal\Core\Form\ConfigFormBase::$typedConfigManager must not be accessed before initialization
in Drupal\Core\Form\ConfigFormBase->validateForm()
(line 161 of /path/to/core/lib/Drupal/Core/Form/ConfigFormBase.php).
I don't know if https://www.drupal.org/project/drupal/issues/3394197 is related. That talks about 11.x but I using latest 10.2.x dev. Maybe the same problem is on both?
Sorry to be be vague, but I'm stuck and cannot save any Devel settings. Any ideas?