Sounds like the power up sequence on the RX side is the issue. Only change I can imagine KT making is somehow drawing power from either the ECU pack or the throttle lead for the ECU with the throttle lead as primary. That would essentially do the the same thing as your Y harness trick. It would take a little redesign on their part as the voltages of the ECU pack and radio system typically are not the same. Otherwise, Spektrum would have to change the firmware in their RX's to "see" telemetry systems after boot/power up of the RX. Or essentially "see" any peripheral device that turns on after the startup. I'm NOT an electrical engineer, so no idea how technically challenging any of this would be for the designers.
My iX12 with the same RX you are using, AR123010T and a K-85, let me set the Turbine option on the telemetry screen. I didn't have it set that way when I did my test runs so I have not seen live turbine data yet on my Tx screen(s). Have not gotten the Telemetry unit to switch from blinking blue light to green light. According to the brief pdf document KT published, blinking blue means the telemetry unit is receiving data from the ECU. Green means it is sending it to the radio system, or in our case, the radio is taking the data.
Thank you for your solution Rick! I've been struggling with this for a few days now. New to turbines and obviously the iX12 is still a "new" platform on the market. I'm a long time Apple guy so learning the Android OS has been a new adventure too. Also having to get use to searching the owners manual through the radio when I do more involved radio setups. I printed a copy of my manual, but it's faster to bring up the pdf on screen, search it and then tap the screen instructions which take me right to the correct spot in the Airware app.
Joe Larson