“Part” not honored, nor defaulted for scheduled series posts (WP 5.2.1_

Use Case 1:

1. Create 11 posts, scheduled for some future date
2. Create a series
3. Assign the posts to the series (don’t define the Part)
4. Preview any post
5. Post Part is not in the order of post creation

Use Case 2:

1. Create 11 posts, scheduled for some future date
2. Create a series
3. Assign the posts to the series (define the Part as needed)
4. Preview any post
5. Post Part is not in the order defined earlier

This is with WordPress 5.2.1