Portability analyzer tool reports not compatible for Array.Reverse example but Microsoft API documentation has it in the examples

Question

I have created .NET core 2.0 project and added the below code

int nMonths = DateTimeFormatInfo.CurrentInfo.Calendar.GetMonthsInYear(DateTime.Now.Year);  
      int[][] months = new int[nMonths][];  
Array.Reverse(months);  

(complete code is available here( jagged array example) system.array.reverse)

when i ran the Portability analyser tool,tool gives report as not compatible for Array.Reverse(months); i.e. Jagged array example but Microsoft API document added that example in the documentation.
since in my current .net core 2.0 project, i have an byte[] data and portability analyser tool report gives as not compatible for .NET standard 2.0 compatibility , i am confused about the result from Portability analyser .
Please suggest your inputs regarding this issue.