I've sent a message off to the OEM for support on IR. As they are in Taiwan and it is the weekend, it may take a few days for a response.
I am testing my Toshiba TV and just using the POWER code as I described, here is the consistent behavior:
Two POWER commands back to back turn the TV on.
One POWER command turns the TV off.
When TV is ON, two POWER commands back to back turn the TV off. However, a single POWER command after that does not turn the TV back on.
It looks as though on this TV at least, there is a concept of a time "window" after the first command is received, where a second command received within that window will actually complete the command depending on the current power state of the TV. It also looks like once the command is executed, the buffer is cleared out to receive further commands.
That is a complete guess on my part!
Can you try doubling up on the commands to see if anything changes? Although I am not an IR expert,I do recall from a different job a few years ago that some IR remotes continuously send the data pattern when you press a button, assuming that when whatever it is you wanted to happen finally does happen, you will release the button.