It could very well be that the resistive load presented by the standard incandescent (Halogen) headlights produced a lower current draw across the headlamp circuit vs. the aftermarket relay (lower resistive load).
From the threads I've read over the years, many add-on HID kits don't appear to work as a simple plug & play (flickering headlights, or intermittent operation). Often resistors are put into the circuit to mimic the load of the Halogen 55W lamps.
The factory programming for HID lights likely has a different load since the circuit is now powering a ballast rather than the filament itself for the Xenon bulb setups.
Depending on the model, there are different electrical architectures - the LX/LY/LC cars have one setup, but it can vary from the other models/lines, and what may work in the Ram trucks and Jeeps can be something very different, or changes in model years.
There's different bus speeds, and Canbus setups can be different as well...how the TIPM is programmed for each vehicle/model can have its differences as well.
2009 R/T 27J pkg (6 speed MT) ordered 7/17/08, built 10/23/08, home on 11/13/08
Eibach Sportline Suspension
Hotchkis Sway Bars
Nitto 555 Extreme 265/50-18"
392 Cam / DS CMR tune
Hurst /G&K modded short-throw shifter