No New Issues of a Certain Type Are Searchable Until Reindex
None of the issues you are creating in JIRA are showing in the associated issue filters. Because of this, they also will not show in any Agile boards, which can cause confusion to a user that might need to do work on that issue. For some reason, reindexing seems to fix this and makes all issues visible in filters and you are now able to search for them. This happens to all issues of a certain type(s).
If this is happening to all issues of a certain type or types, such as Bug tickets or Enhancement tickets, check the associated workflow. Under Text view, select the first step in the workflow, usually titled 'Open'. After selecting that, select the transition to the left on the diagram titled 'Create' or 'Create Issue'. Under the post functions of that transition, you will notice that the post-function called 'Re-index an issue to keep indexes in sync with the database' will be missing.
Edit the workflow as a Draft and select 'Add Post Function'. From there, add back 'Re-index an issue to keep indexes in sync with the database'. After that, creating an issue will automatically trigger the instance to reindex the issue and it will be searchable immediately.
*Please note that the 'Re-index an issue to keep indexes in sync with the database' Post-Function is not easily removable from the 'Create Issue' transition, so this will not happen under normal circumstances.