Just conjecture on my part.
Neither the charger nor the vehicle can detect the temperature of the wiring. The incoming voltage can be used to infer the wiring resistance.
The software could monitor the incoming voltage and if it senses too large a drop, throttle current. After charging for a while, suboptimal wiring may heat up causing an increase in voltage loss. The changes included in the May upgrade could have tightened the voltage drop limits, causing previously working charges to be throttled.
Neither the charger nor the vehicle can detect the temperature of the wiring. The incoming voltage can be used to infer the wiring resistance.
The software could monitor the incoming voltage and if it senses too large a drop, throttle current. After charging for a while, suboptimal wiring may heat up causing an increase in voltage loss. The changes included in the May upgrade could have tightened the voltage drop limits, causing previously working charges to be throttled.