Line thickness when exporting from pptx to pdf - what's the problem?

Question

PowerPoint

Faced the following problem:
There is a pptx document created in Microsoft PowerPoint 2013.
It contains the following objects:
1. A straight line with a tip 0.25 pt thick
2. A straight line without a tip 0.25 pt thick
3. A rectangle without a fill with a border thickness of 0.25 pt
4. Photo with a 0.25 pt border
Everything is black RGB 0 0 0
When exporting to PDF via PowerPoint, the following happens:
1. becomes 1 pt thick, color black
2. becomes 0.25 pt thick, color black
3. becomes 0.25 pt thick, color black
4. becomes 0.25 pt thick pt color black
Can't get over problem with export 1 -> 1.
In this case, it seems like 1 and 2 are the same object.
If anyone can help I would be grateful.
Screenshot from PowerPoint:

Screenshot from Apple Preview.app (Google Chrome and Adobe Reader give the same display):
.pptx file on Yandex.Disk
.pdf file on Yandex.Disk