Given this code, .NET outputs the enum value names correct. IL2CPP does not:

using System;

class Program
{
[Flags]
enum MyFlags : uint
{
One = 1,
BigNumber = 2448949181
}

static void Main()
{
Console.WriteLine(MyFlags.One);
Console.WriteLine(MyFlags.BigNumber);
}
}

>csc test.cs
>test.exe
One
BigNumber

>il2cpp test.exe --outputpath=test_il2cpp.exe
>test_il2cpp.exe
One
2448949181