This is a known issue of Harmony remotes. Sometimes, they only 
insufficiently learn Apple Remote codes. Instead of sending the 
correct IR sequences

[PRESS .... STILL_PRESSED .... STILL_PRESSED ....]

for a single button press, they're sending multiple presses:

[PRESS] [PRESS] [PRESS] [PRESS] ..

There's nothing Remote Buddy can do about this. It reacts to the 
signals as it receives them.

The only solution available is to retrain your Harmony until it 
recognizes and subsequently emulates the Apple Remote code correctly.

Best regards, 
Felix Schwarz