Function acts volatile even though it is set to false

[simemese]

We have functions in this structure that act volatile even though they are set to not be volatile (e.g. recalculates if a row is added). Does anyone have any idea what are doing wrong?

[ExcelFunction(Description = "Grabs available curves. Please specify the quarter in this format: 2020Q4.", IsVolatile = false)]
public static string fl_DownloadCurves(string quarter, string filePath)
{
try
{
if (String.IsNullOrEmpty(filePath))
{
filePath = @"B:\Curves" + quarter + ".xls";
}

            Curves curves = new Curves(filePath);
            return dataStore.AddObjectAndReturnKey(curves);
        }
        catch (Exception ex)
        {

            return ex.Message;
        }
    }

[govert]

You are not doing anything wrong - you are seeing normal behaviour for any function in Excel, unrelated to the 'Volatile' concept.
Excel recalculates the sheet when making structural changes like adding or deleting a row or column.

Compare the behaviour of a VBA function like this:

Function Increment()
    Static i As Integer
    
    i = i + 1
    Increment = i 
End Function

With a volatile function like =RAND(), putting both into a sheet.

You'll see that only the volatile function =RAND() calculates when you edit some unrelated cell on the sheet, but both calculate if you add a row.

[simemese]

Thanks! Ended up caching the results and returning if they already exist.

https://excel-dna.net/2013/04/02/caching-and-asynchronous-excel-udfs/