Found this info on Aaron's website. Don't know anything about it other than Aaron is an experienced user.
Uncut Angling
May 11 at 10:08am ·
HUMMINBIRD USERS: Do NOT download the latest April 17th software versions for your Helix (1.400) or Onix (3). It is causing issues with AutoChart Live mapping for me and others. It may not affect your unit or waterbody, but at this point I would hold off on the update unless you absolutely need it for some other compatibility reason.
Mike