Thanks for you patience while we were investigating the case. We've managed to get correct output to PDF file, but there's quite specific situation with the presentation itself. Please read further for details.
1. Left side bullets with right-to-left text is a strange combination, but it's manageable. We've made an adjustment to Aspose.Slides to handle it. This fix will be available in Aspose.Slides 16.8 release.
2. The text on the slide #20 with hebrew language doesn't look correct. We consulted with a native speaker and he said that the text as it is in the original presentation you sent us has some issues with its meaning. The word "המאושרת" is misplaced as well as full stops are positioned wrong.
The further investigation showed that the presentation has some missing data in its structure. None of the textboxes in presentation has a record with Lid (Language id) specified. As well as undefined Bidi (bidirectional/right-to-left) flag.
A small note. In ideal situation every text fragment should have its Lid specified. This value comes from current language settings of operating system when user inputs text manually, or it is extracted by PowerPoint from clipboard text properties during text pasting (but that is not always possible and it looks like your case). Missing or wrong Lid value can result a misinterpretation of text content - that's more likely be an issue of right-to-left languages, so in the original presentation only the slide with hebrew language faces this problem.
We added this missing data to the slide #20 and that works. The presentation started looking better in terms of language sense (the word "המאושרת" and full stops are placed correctly). Also now it looks the same in PowerPoint, in PDF file exported from PowerPoint and in PDF / image files exported from Aspose.Slides.
Here at that point we kindly ask you if it is possible please share with us the information about the purpose of the presentation.
1. Is it a test file to check languages are handled correctly by your service or/and Aspose.Slides?
2. Is there a chance you'll get another presentation with hebrew text from computers without hebrew language installed?
If you get this problem again and decide to fix Lid/Bidi values in presentation file, we can investigate how to automate the process once you request it. For now we hope that you can use corrected version as it is. Please notice once again: we didn't change the text itself, we just add a few missing records to ppt file structure.
You can find the corrected file attached.