Teaser is missing CKEditor when uncollapsed I have text with summary fields on my entity and for some reason the ckeditor is present only on the body, not on the teaser if I uncollpse it. What could be the issue?
Never use "Text and summary" fields. It's a sad/unfortunate fact that Drupal 8 didn't manage to remove them.

Instead, create a separate (independent) summary field.