I had to sign up for Evernote Pro to be able to look at note history. I was able to recover the content that way. I got a monthly subscription, so figure I can cancel in a couple of months.
Most of the content for one of my notes has disappeared. In the All Notes window of the web version, the thumbnail in the left column shows original content for the note, while the actual note in the right column shows only six lines of the original several dozen lines. Same content has been lost on my Android phone as my desktop. Screenshot is attached. I have the free version of Evernote, so don't have access to Note History.