It is possible that learned codes use an entirely
different transmission/modulation circuit.
Admittedly, I am grasping at straws with this
sugestion.

As to why hitting the buttons over and over would
help, it is probably due to slight differences in
the orientation of the remote, and brightness
variance from place to place in the light cone of
the LEDs, combined with the fact that it is
probable that every time it fails it is failing
by the narrowest of margins.

Has anyone tried MASKING tape to obscure the
sensor? It is more opaque, and fewer layers
should be required.

-=Ingenious=-