I checked the manual and it’s actually documented to trip at 137V and open its fault relay, and won’t reclose until the input voltage drops to 134V. This is hidden in the fault section and not really advertised in the specs.
Obviously in a cold weather overvoltage situation this loss of load causes immediate runaway, which resulted in many full days of lost generation until I rewired the array down to 2s strings.
This issue was actually what resulted in me building the first dump load for the system, because as long as I kept the array loaded enough it wouldn’t trip out. No way I was breaking the connectors or my fingers off during several weeks at -30C!