CheckinFiles LocalFileState=new doesn't work

Studio 2017SR1

GS 2017 SR1

Hi there,

don't have success following this instruction "producthelp.sdl.com/.../5457cb35-5a41-432a-8f37-058ae23f2c4f.htm" to checkin new files.

I'm adding files with

_tradosProject.AddFiles(files);

to an existing Server Project, which works well, so far. But checking in this file, doesn't work:

_tradosProject.CheckinFiles(new Guid[] { file.Id }, "common", StatusEventHandler);

Nothing happens here. Even Fiddler is quite as nothing is transfered to Server.

Checking in files in Studio by hand (Project updated by this process) works well, and Fiddler also logs some SOAP Actions (including checkin files).

Any ideas, what I'm doing wrong? Is this a bug and if so is this fixed in Studio 2019?

Cheers

Markus