The “test 2” issue was related to the fact that the index table engine does not index words below the length of 3 by default. It most cases that is optimal, but in yours it might not be the best option. I've changed the minimal word length to 1 on the index table options panel and re-created the index table: https://i.imgur.com/SByLmvO.png
Now it should return the correct result.
I'm guessing when a user submits a post, it's still stored as if your account was the author, and the real author is stored within a custom field. When the search requests the author, wordpress returns your name.
Luckily there is a way to get around that. I've put together a quick code snippet for you to get the author name from the custom field.:
You can put this code into the functions.php file in your active theme directory. I hope it will work.Best,
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