Won't start with 100% charge

I have a KIA Soul 2017 which whenever I charge to 100% and try to start the vehicle the High Voltage battery level Warning light comes on and the Immobilizer Indicator light comes on. The only way I can start the car is by disconnecting the 12 volt battery and reconnecting it. The car works fine once I do that. It stopped doing that for a while but now its back. I only have 500 mi. on the car. Gave it to KIa but its intermittent so Kia is having a hard time finding it and I really don't like there Loners. Any Clues?

Have you replaced the 12v Battery ?

Others members with this sort of "bug" ... has been associate to a replacement of DC-DC converter (integrated in the motor-controller) after a regular (and under WARRANTY) replacement of the 12v ACID Battery.

On IoniQ, the DC-DC converter is integrated in the Charger.

They replaced the 12 volt batt. That's all. but your saying the converter might be the problem? and thanks for the reply.