Derating happens when an inverter responds to internal or external inputs that prevent it from producing full power.
Derating due to External Ambient temperature. Event Code 10501
One inverter is reading 26C outside (C2) and the other is reading 59C outside (C1)
So hot air from the HS is blowing onto the sensor (filters need to be cleaned?) or the temp sensor is damaged or needs its connections checked. This sensor is under the hood and gets reading from the external air passing into that chamber.
Check the connections on X20 on the MMTCON board. Otherwise order a new temp sensor!