event filter on exactuei yields unexpected results

I entered a partial string "uei.opennms.org/internal/importer/" in the ExactUEI field on the advanced events search page. After clicking the Search button, I expected one of two results:

a) a page of events limited to those whose uei strings partially matched on the UEI.

b) an empty page of events.

I got neither of those.

What I did get was a list containing the most recent 10 events.