@BrittMoore1 , @IvanZheng or anyone else - have you sent this to Instructure Support? I just did asking them to read these comments and look into it, and they responded "Could you please, give us more details so we can take a better look at this behaviour? We will need a link to the specific item that the search shows, the term used to search for it and a link to the person's account who ran the search or you acted as when searching for the announcement."
Surely they can try to re-produce this problem themselves...or maybe even one of the Instructure employees responsible for this forum?
There are certain types of announcements that teachers do NOT want students seeing before it is published or unlocked, so I believe this is bug that needs to be prioritized. The same goes for the other bugs regarding unpublished course content that Smart Search shows students -- Instructure can easily take a look in the forum and prioritize these things.