I searched around and saw that this happened before 2.7 but that isn't the case for me.
When I click "edit" on a post it will be in html mode. When I click on "visual" all of the text will disappear. I can click and drag and see that the text is still there but it remains in html mode.
Again I see there are similar issues to this pre-2.7 but nothing exaxtly like this, and this only started happening today after I upgraded.