When converting PPTX document to XPS its formatting is broken.
Please note, I tried saving this PPTX document to PPT format and than convert it to XPS and in such case formatting was correct.
I attached presentations and their XPS versions for example.
I have worked with the presentation file shared by you and have been able to observe the issue. An issue with ID 29498 has been created in our issue tracking system to further investigate and resolve the issue. This thread has been linked with the issue so that you may be automatically notified once the issue is resolved.
Thanks and Regards,