Store search returns random results

I’m encountering an issue with our store’s search function that I haven’t been able to resolve. Normally, when I search for products by name or keyword, everything works as expected. But when I search using the SKU, the search results show 10-30 completely unrelated products that don’t match the SKU entered. This random result issue started about two weeks ago, and we haven’t changed any settings in years. We’ve been using the same product and store settings for a long time, so I’m not sure what could have triggered this issue. Has anyone experienced something like this before or have suggestions on how I can fix it? Thanks for any advice or help!