Prius does not shut down the engine when stopping

A few day ago I noticed my Gen2 Prius with 260.000 km logged in did not shut down the engine when stopping, ie at red lights and so on. I used my bluetooth scanner and it gave me the code P0505. Looking online it seemed to be related to the throttle body, so I bought a cleaner and cleaned it as best as I could (without removing it).
Now, everything seemed to be ok for a couple of days, now after a longer trip, on top of not shutting down the engine, when I come to a stop it just idles at very high rpm for a few seconds and then calms down, so after the cleaning it seems to be even worse due to the high rpm idling

Other than that, the car runs as well as always. I don't see anything wrong with it. If anything, it seems to shut off the engine faster now, compared to before the cleaning, at least before the issue manifests itself again.

Please, explain to me what I can do to fix or mitigate this issue. Why is the engine idling at high rpm after cleaning the throttle body? What else could be preventing the engine from stopping? I know the engine will stay on if you have AC running but I'm not using it these days. Other than that, sometimes when the hybrid battery is very low, I know that the engine will run to charge it, and on the display you'll see the arrows indicating that the battery is being charged. When the issue begins, usually in the middle of a trip, the engine is just on but the battery isn't being charged, according to the display, or it may be at 8/10 or even 9/10 bars and still the engine won't shut off.

By the way, my prius has the EV button, if I press the button the engine shuts off just fine and the car works on electricity only.

And one last thing that may be (possibly?) related. A few days ago I forgot to turn off my headlights and drained the 12V battery so the car would not start. I jumpstarted it as usual and went home just fine. Could it be that the car is just trying to charge the 12V battery maybe? Just wishful thinking on my part tbqh. And even if that was the case, I still have a very high rpm idle for a few seconds after touching the throttle body

 

Btw, I just took the car right now for a short trip, it ran flawlessly. I don't understand. Maybe I'm overreacting and it's fine now.