This has happened to me several times before, but always only 1 note at a time. This time I lost major updates to FOUR NOTES---but not ALL of the notes that I was working in during that specific time frame (only the most important ones---ARGH). These were very important to me (I have been trying out using EN to write articles), and I am very displeased. I'm using the desktop version and mobile. The issues are with the desktop version, and I did not open the problematic notes in mobile in the interim. I made sure multiple times that each document was saving (i.e., I check that I was receiving no notifications of issues AND I clicked save and watched the "dots" complete their circuits).