bug or a general misunderstanding

Hello there

I'm not sure if I'm in the right place here.
Maybe it's a bug or a general misunderstanding of how GIT works.

The following situation: I wanted to create a branch from a commit. From 
there on the work should be continued.

The possible bug:
The newly created branch is missing commits in the history. Not only are 
they not displayed, the code changes are not present.
It doesn't matter if the branch is created by Visual Studio or GIT for 
Windows.
Only in a branch created by GitHub Desktop the commits are present, as I 
would expect.

Is this a bug or do I not understand how GIT works?

Best regards and thank you for the effort
André Pohlmann