I've discovered this is true of other buttons on the OEM remote, too. Moreover, it seems that after the OEM remote "rests" for awhile it will emit an IR signal on the first press only. After that, it won't until it rests for awhile. The first rest period seems to be only about 15 minutes. After that, it seems to be a much longer rest period. It may be that the television has to be off during the rest periods.