If you have edit notifications from “system” for posts from Google+, it is because I am running a script that is adding previously-missing images to the posts that were previously missing from the import, and the mechanism I am using for doing this shows up as the “system” editing your old posts. I apologize for the noise.
Rather than figure out how to avoid that, I’m just going to do it all at once and finish the job. My apologies for the noise in your notifications! I’ll call it a feature: You now will know which of your posts have been updated!