For minutes at a time during the day, the Activity stream will only show non-Jira stream events (structure, bonfire, tempo, etc) and not any Jira activity. A few minutes later, it will start working again. This happens regularly and periodically throughout the day.

I'm not sure if its a problem with the Activity Stream gadget itself, or if something is happening on the backend (like reindexing) that makes the search return no results.