From my understanding, delayed query execution and file not found is not related. The file not found could be caused due to delayed query execution. Consider you are loading a page and due to the complexity of the domain model or un-indexed huge dataset or other various reasons, the query executed could possibly be delayed.
Which could possibly lead to page not being properly loaded and file not found.
In this case, you should look in to the details of the query and its associated domain model, optimize the retrieval or query execution. When not addressed this could also lead to java runtime errors like out of memory or no database connections. But it will be hard to track where the issue happens.