Interesting. I looked up the tail number on Flight Radar 24 and Flight Aware and it shows a couple of flights around Shreveport, one of which was from Shreveport to Tulsa, and then three or four short flights around Tulsa. All of these were April 11th and 12th and nothing since.
Looking at departures and arrivals for TIA there's not much if anything between about 10 PM and 2:30 AM. I don't know how much traffic there is out of Riverside after dark, so the air space is quite empty over Tulsa at night. It could be that they broadcast their transponder to ATC but it's not publicly relayed. I know that when F-35's and others fly out of Luke AFB just west of where I live they don't relay their transponders to either Flight Radar or Flight Aware but they do transmit to local ATC. because they do cross the far western edge of the pattern over Phoenix.
I don't think legally TPD could fly dark, no lights or transponder, regardless of what the traffic level is over Tulsa.