I appear to have found a bug with the MergeNamedStyles function added recently. Please run the following top-level code (adjusting the file paths as needed) with the attached zipped workbooks as a .NET 9 C# console app
…...Worksheets["Map"]; if (sheet != null) { targetWbk...targetWbk.Worksheets.RemoveAt("Map"); } DeleteStyles(targetWbk);...