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I think the order of operations leads to a loss of precision here. From Sharplab:

Console.WriteLine(DegToRads1(double.MaxValue));
Console.WriteLine(DegToRads2(double.MaxValue));

static double DegToRads1(double deg) => (deg * Math.PI) / 180.0;
static double DegToRads2(double deg) => deg * (Math.PI / 180.0);

Output:

∞
3.1375664143845866E+306

That’s expected due to the type precision and input domain (as well as general limitations with how we can validly implement the DIM).

The same thing can happen for other pairs of functions as well (like exp and log, cos and acos, etc)