Created attachment 153812 [details]
Testcase in PPTX format
The Text formatting is destroyed after a PPTX file is saved as .ODP and opened again.
It is fine after openeing the PPTX.
* Open the attached PPTX
* save it as ODP.
* Close LO
* Open the saved ODP
Created attachment 153813 [details]
This is a screenshot of the destroyed formatting
LibreOffice tries hard to import "SmartArt" from MS Office documents. There has been recently a GSoC-project to improve it. But still a lot is missing. As workaround, you should convert the SmartArt-object to shapes in PowerPoint (It has an option for that), if that is possible for you. Then showing it in LibreOffice works.
I can confirm the error with
Version: 188.8.131.52.alpha0+ (x64)
Build ID: b5f4041ef04f6645cbd91d35f6231573e3042636
CPU threads: 8; OS: Windows 10.0; UI render: default; VCL: win;
Locale: de-DE (en_US); UI-Language: en-US
@Grzegorz Araminowicz, I thought you might be interested in this issue...