Acrobat Reader DC Does not show PDF as expected

Hello folks!

I am a software developer at a small company in germany. We programatically edit PDF form fileds and fill them with customers data for our clients.

We use the PDF-XChange Editor to set form field names and properties etc and our clients and customers are mostly using Adobe Reader for viewing these PDF's.

Now i have the following problem:

Some PDF's contain small calculations, like adding some fields up. After we processed the PDF with a .NET Library and open it in Adobe Reader DC the calculation partly does not work any more. But if i open the same file in PDF XChange-Editor the calculation just works fine.

We also tried it on different machines, but we got always the same result.

I have attached the PDF i am talking about. On page 20 are the calculations. The left one, labeled SUMME, just works fine, but the right one, also labeled SUMME is broken. 

I am using the Adobe Reader DC version 2019.021.20056 if this helps.

Now i try to find answeres to my questions and i hope maybe someone here had a similiar problem or can help me.

Hopefully i described my problem clearly, if not please do not hesitate to ask!

Kind regards

Arnd