[Koha] No search results

We updated to 3.8 recently and then had trouble with searching - items would show up appropriately in the search, but they would all say "No items available". After some difficulty, our IT tech was able to reindex zebra and the item availability is now correct. He set the reindex to run nightly as we are a small library that only adds new materials weekly. However, I'm now having a problem with items not being found on search at all. Most searches show "no results for..." - this is for older items and recently added items. I believe these items were coming up in search before the reindex (although they all said no items available). Any suggestions?