I moved all the items from a collection to another. However, these items, on the source collection,didn't appear on the discovery. After the move, these same items appeared on the destination collection. Why these items didn't appear at the source collection before the move?
Still before the move: If I get these item's handle and try to access on a browser it works. Should it be a problem on discovery index?
There could be 2 causes for this issue.
Here is my recommendation.
The re-index can take a while a while to complete. User search results will be impacted during the re-index process.