When I initially set up I had the beolabs playing by using the remote and then pressed play on the ir eye. After I disconnected the beloabs I used the remote to control the ir eye.
Just to be sure about the setup: Is it correct that you do not have any speakers connected directly to the Beosound 9000?
Only two things occurred between it working and not. I used the remote to turn on a non-b&o tv, and an electrician changed a dimmer switch.
Hard to say if these things could have affected anything, but anything is possible.
The IR eye had a loose connection so I replaced the lead for a new one. I
Did you replace the lead with an original one with the same color coding? If so did you double check that all the wires are connected correctly and that there is no strain from any of the wires touching anything than its dedicated screw terminal in the IR eye?
Link to connection drawing here
/api/files/7c34c9eded4f444ca20b2ab713a54fb7
find it odd how the IR eye is receiving a signal from the remote (it blinks when I hold the OFF button or blinks when I follow the process you showed above) but cannot process a proper command.
I think that the IR eye might be able to react if just ground and 5V is connected, but if there is an issue with the data wire the signals might not be passed, so it is possible that there can be an issue with connections as mentioned before.