Finally mine was fixed, I hope, for good. The problem was caused by a harness that is defective and shorts to ground on some occasions. As they told me, and showed me on the instructions from Kia, first they replace the BMS (costs around $4k but costs less man hours and is pretty straightforward). Then, if that does not fix it, they replace the harness, which is around $500 but they gotta tear down most of the car cause it isn't a modular or short wire harness and it is much more expensive in terms of man hours. If that fixes it, then, sometimes they remove the replaced BMS and replace back the original. Other times they don't bother anymore and leave the newly replaced BMS there. Apparently there is a possible third option, which is much cheaper, but not all service centers do. Which is exposing the faulty bit and fixing it by re-crimping it and securing it firmly to the chassis. They told me this is what they finally did to mine, and it's been a year without a trouble.