Pasting text into content (post scheduler) bug

Pasting into content box works AT FIRST, but then once you publish/post and look at the file in Express - that text was pasted on top of my first image! Yikes! I've had to delete several posts. I am assuming it's a bug. It's been happening for a few weeks. Browser: Chrome. 

Showing the issue:

https://www.loom.com/share/ff7a861c4339436fbd870cc4cc03b32e?sid=c27f99d5-feaa-4070-b601-3f99cb01c196