Pasting Deletes Content

[eccogrinder]

Describe the bug
Pasting text into the body of a post will oftentimes (but not always) delete all the content in the post. (In other words, pasting replaces rather than adds content to the field.)

To Reproduce
Steps to reproduce the behavior:

1. Create or edit a post
2. Add text into the post
3. Paste an additional chunk of text.
4. See error

Expected behavior
I expected the text to be pasted in without deleting any other text.