Since aspose version 21.2 the chart titles in excel outputs are no more horizontal. In pdf or print output the chart titles are correctChartTitle.zip (207.2 KB)
Please try our latest version/fix: Aspose.Cells for Java v21.2.3:
aspose-cells-21.2.3.zip (7.1 MB)
I have tested your scenario/ case using your sample code with Aspose.Cells for Java v21.2.3, it works fine and the output Excel file is ok. Please find attached the output file and let us know if you still find the issue with latest version/fix.
files1.zip (8.3 KB)