Ah! Perhaps it's only words like to counsel (counseled) or to libel (libeled); up in Canada here people usually write counselled or libelled.
dueled, paralleled, canceled, pedaled, but controlled, compelled, extolled, appalled
levered, snickered, but occurred, deferred
focused, biased, censused, but compressed, embussed, outgassed
worshiped, but entrapped (although even in America kidnapped seems more common than kidnaped—one of Webster’s less successful reforms)