Much of the context is in dotnet/coreclr #13388 [1].
At the risk of repeating the content of the blog post ... The issue was reported in August, 2017 and fixed later in the same month. The fix shipped in a .NET Core patch update in September. We attempted to get the fix into .NET Framework 4.7.2 but missed that scheduling. We're now looking at making the fix in a .NET Framework patch release.