LuceneService.waitForFlushed does not wait if members have been restarted

We wrote a test that

• puts 10K entries,
• pauses the async event queue
• removes the same entries minus 1
• Closes the cache in the data stores
• Recreates the cache
• calls LuceneService.waitForFlush
• Does a query to LuceneService ensuring only 1 item is in the cache

This test fails consistently, even though we would expect waitForFlush not to return until the queue has been fully processed. Running the same test without closing/recreating the cache succeeds consistently, so there seems to be an interaction problem between some combination of the queue, cache lifecycle and waitForFlush.