Why does searching by a specific author (me) produce posts written by other users?
pick a community space, then enter your name and hit enter and it will be full of Bud posts for a space.
Searching for every idea for every community is really a no-go because you get the hits with "idea"
@Bud, try clicking on the "Show me results in comments" highlighted text beneath results that show a different member as the parent post author. What you're likely seeing is that these posts are included because you are the author of one or more comments in the post.
Here's an example of me searching for posts by myself where some of the the search 'hits' are responses on posts authored by others.