When you perform a "long left" press, is the action assigned to "left" executed instead by any chance?

Reason I ask is that the Harmony series of remotes often has problems to a) correctly record and b) correctly send Apple IR codes. I've seen Harmony remotes send any of the following:

1) the IR code for a short button press (once - regardless of how long the button is pressed)

2) the IR code for a short button press (multiple times, in quick succession - resulting in multiple short button press events getting generated for a single button press)

3) the IR code is sent correctly

Have you trained your Harmony Remote yourself - or are you using the pre-made "Apple Remote" profile supplied by Logitech?

Ah, and depending on your Harmony Remote model, some buttons simply don't support long button presses. They'll generally only send short button presses - even if the previous recording/training went right.

Best regards, 
Felix Schwarz