@mrjonboy - I tried it myself on both FireFox and Chrome and experienced the same problem as you. Sometimes it worked, sometimes it didn't.
We've been having problems with the latest version of the HTML editor we use, and are in the process of replacing it. The "labs" version of Method has the new HTML editor, but the web forms is a separate application, and still has the old HTML editor. I've put a ticket in to get that replaced too.
For now, I found an awkward workaround that always gets it to work properly for me when it gets "stuck". It's bad that I'm asking you to go through these steps, but at least it will get you the desired results until we have an update.
1. Change the tab from "Design" to "Preview" on the HTML Editor.
2. Change the "Get email from" from "Dropdown" to "Textbox".
3. Change the tab back to "Design" on the HTML Editor.
4. Change the "Get email from" back to "Dropdown".
Then the HTML Editor gets unstuck.
In terms of the original problem. We have a developer looking at it. It appears that the error we saw in the logs was when the grid in step 8 loaded. We're still unsure why that error came, or how to reproduce it, and we're still not sure if that is related to why you experienced a data loss when you saved. I'll let you know as soon as I hear more.