I have been periodically testing USB-C trigger boards and cables because I eagerly anticipate a future with no wall warts, no 5.5mm barrel jacks, no mystery meat voltages and no copy/pasted incorrect barrel jack diagrams.
However, the first generation of USB-C trigger boards all had a huge problem: if the voltage wasn't available or if negotiation failed, they didn't fall back to 0V output (perhaps with a little red light or other hint), they just picked a random lower voltage from the bargain bin and gave it to you. "12V? Eh, best I can do is 9V, enjoy!" Of course, they also frequently put out 5V before they put out the final negotiated voltage, whatever it is. This obviously saves a few cents on a power transistor but it is just as obviously makes the trigger board completely unsuitable for anything not designed specifically to tolerate it. Devices going forward are probably fine, but this behavior makes retrofits a complete non-starter. "Eh," I thought, "most products have glaring issues in their first incarnation, I'll just wait it out." Well, it has been years, the generations of USB-C trigger products have turned over, but the "voltage roulette" behavior seems to not only have survived but still completely dominates the market.
Wtf? Am I using the wrong search terms? Is the world populated entirely by masochists who love debugging surprise brownout issues? What gives?