I noticed when I first click on the search left nav item, it says no results are found.
I believe this is as intended.
However, I noticed when I click into custom search results (like a format) and click back to main, the results of the format remain.
I am not sure this is a bug or not (seems inconsistent) so filing for analysis.
I've attached a video in case I'm not explaining well.
The results seem to persist until you refresh your browser or you login to an account with different permissions.