I felt it would be best to update this thread, as I have dropped the vehicle off at the dealer due to the "continuous intermittent" problem of the flashing center diff lock indicator.
So yesterday, the light came on upon start up. I have noted that it only comes on during start up and the continues to flash continuously until the engine is shutoff. Whether or not it comes back upon the next start up seems to be based upon a druid's prayer somewhere in the eastern UK, while waiting upon his mother's father's great aunt's cousin's brother's uncle to show up.
Well, yesterday was the day... so I stopped off at the dealer to show them the indication and get them to troubleshoot the problem. They did see the indication, noted that the vehicle would NOT shift between 4H and 4Lo, would not engage the center diff lock, and that the VSC and warning lights were NOT on. That all said, they called Lexus and were told...."Operator Error".
I lost it!
So, I did have a length conversation with the service rep and they are repeatedly starting the vehicle over the remainder of the week to replicate the initial instance of the problem, since for some reason they feel they have to be the one to do that before they can determine whether or not the vehicle has a "problem". Yes, the frustration has set in... yes, I am thinking of returning the vehicle... yes, I may need counseling after this week.
I will continue to update the thread with any pertinent technical information to help any other poor soul with the same problem.
Jonathan