This repository shows the difference between Math.Pow(1,double.NaN) in .Net Framework vs .Net Core
In .Net Framework Math.Pow(1,double.NaN) results in double.NaN, whereas
In .Net Core Math.Pow(1,double.NaN) results in 1.0
According to the documentation https://docs.microsoft.com/de-de/dotnet/api/system.math.pow?view=net-6.0 the . Net Framework behaviour is the correct one.