For those of you with similar situation as mine; it turned out that the xenon control module was not defective. Parts of the wiring harness in the headlight assembly had stopped working which could explain why the replacement of the xenon control module only temporarily solved the low/high beam malfunction.
I sourced one used passenger headlight which has now been installed over a week. Low and high beams are still shinning bright without any error messages.
If I had requested that the original xenon control module on the passenger side (believed to be defective) also be swapped with the driver one, I could have saved $$$ by having another party do a diagnostic to isolate the problem to a defective headlight. Only the driver side module was tested on the passenger side as you can read above.