VS2017 repeatedly appends GlobalSection to solution file

VS2017 v15.9.3, every time I open the solution file, it marks the solution file has changed. When I view changes, I saw the same guid gets appended again and again. Is this a VS bug or AnkhSVN bug?

Global
    GlobalSection(SubversionScc) = preSolution
        Svn-Managed = True
        Manager = AnkhSVN - Subversion Support for Visual Studio
    EndGlobalSection
    GlobalSection(SolutionProperties) = preSolution
        HideSolutionNode = FALSE
    EndGlobalSection
    GlobalSection(ExtensibilityGlobals) = postSolution
        SolutionGuid = {guid}
    EndGlobalSection
    GlobalSection(ExtensibilityGlobals) = postSolution
        SolutionGuid = {same guid gets repeated}
    EndGlobalSection
EndGlobal