In exploring the new character sheet, I went to change levels on one of my characters. In doing so I went into the description area to edit the backstory. The current note didn’t come up. I closed the window and my pre-existing note disappeared!

I pulled up a different character, edited the backstory (which was blank this time). I added the word “test” and closed it. It remained. Then I edited it again and it was blank. The word “test” no longer exists.

This is using Safari on an iPad Pro 10” with iOS 11.3.1

I'm having the same bug.  In the character builder, not the sheet, right?

Right