I have read on some other forums that MS update KB3035583 is causing some issues similar to yours. It is the main update that places the Windows 10 upgrade icon in the systray. Try uninstalling it and see if that helps. I would then hide it when it appears again (you'll need to change auto updates to manual at least temporarily to do that)

You can always manually choose to install Windows 10 in the future without that systray icon anyway.