Tasks browser keeps tasks that no longer match the search

I have my Tasks Browser set up to show me unresolved tasks from my JIRA system, with the following query:

assignee = currentUser() AND resolution=unresolved order by rank, status ASC,updated DESC, id ASC

When I start IntelliJ, I have a task whose ID is ABC-123, and whose status is OPENED. It is therefore on the list, because it's unresolved. I work on that task, and then I finish it. I go into JIRA and change its status to CLOSED.

When I run the above search in JIRA, ABC-123 is no longer shown in the search results. Great!

However, if I refresh my Tasks Browser in IntelliJ, ABC-123 is still in its list.Not great!

If I restart IntelliJ, ABC-123 is not in the Tasks Browser list. Good!

So it would appear that the refresh function in the Tasks Browser is additive, not a "clear and load" as I'd expect. To confirm this, I did a little experiment:

1. Set search to something altogether different, that returned a completely different set of results. Call that Result Set A.
2. Close Preferences and refresh the Task Browser.
3. See Result Set A (and possibly other stuff, but I didn't bother checking)
4. Open Preferences and change the search to something that returns Result Set B.
5. Close Preferences and refresh the Task Browser.
6. See Result Set A AND Result Set B.

Yup - it's additive, not clear-and-load.

I have tried this with issue cache turned on, and with it turned off. No difference.

Anyone have any suggestions?