LearnDash won't save new content to lessons

Loom Video:

• https://www.loom.com/share/d87fbc457d4f4afcb015cb435d290a96

Problem:

A LearnDash lesson is created, saved, put into the course. 

Then later, changes to that lesson are not saved.

Changes can be made to POSTS. Not lessons.

Recently actions:

I did remove a lesson. Made that prior lesson into a topic. Added the topic to the course with the builder.