Starting with Aspose.Cells for Java 21.7 and up to 21.11, the PDF exported out of a Chart instance with the operation toPdf is truncating the chart title in some cases.
This issue is more noticeable since, for the same Chart, with the same settings, the operation toImage exports a .PNG image of the chart which properly includes the entire title.
Please notice, I am able to reproduce the issue as you mentioned by using your template file. I found that chart title is truncated when exporting to PDF in newer Aspose.Cells for Java versions. The issue is logged into our database as following:
CELLSJAVA-44094 - Chart title truncated when exporting to PDF
We will look into it to figure it out soon. Once we have an update on it, we will let you know.