Thanks for considering Aspose.
I think you are using Aspose.Cells for Java. I tried the following code with the latest version / fix and it works fine, I check the output file and the formula is calculated fine:
Workbook workbook = new Workbook();
com.aspose.cells.Cell cell1 = workbook.getWorksheets().getSheet(0).getCells().getCell("B7");
Kindly try to replace " ; " with " , " in your formula.
Which version you are using?