Multiple boolean search restrictions involving the same property crash Crowd

So I'm just trying to make a normal search on groups in Crowd containing a collection of SearchRestrictions.

(The following code is in Groovy—the Textile code renderer doesn't support it)

def results= crowdClient.searchGroups(
  new BooleanRestrictionImpl(BooleanRestriction.BooleanLogic.OR, [
    new TermRestriction(new PropertyImpl('permission', String.class), MatchMode.EXACTLY_MATCHES, 'read:group:CROWD-Administrators'),
    new TermRestriction(new PropertyImpl('permission', String.class), MatchMode.EXACTLY_MATCHES, 'manage:group:CROWD-Administrators')
  ]), 0, 10)

Individually, both of these queries take a fraction of a second to return results, but if I try to combine them in a BooleanRestriction, the resulting query pins MySQL and the Crowd Client eventually times out.