I was thinking that maybe it might have something to do with the recall on the connectors where if someone hits them with their feet (passenger side) then it can make the pins move and increase the resistance and cause them to get hot and start burning
"For the surface treatment of the connector installation location and the connector terminal of the power transistor for controlling the blower fan air volume is inappropriate, if applied external force by the occupant of the foot such as the connector, by the contact portion of the connector is a deviation, the contact resistance is increased sometimes fever temperature becomes higher. Therefore, the melting connector by its repetition, in the worst case, the blower fan becomes malfunction, there is a possibility that the defroster is ineffective"
This is from the translated recall notice I got from my car's history report that had this issue fixed.