Deviation of Milling result -1mm

Dear Friends,

Setup:
D840
UCCNC
VECTRIC V11.5

I am desperate, to say the least. All my stuff that I am trying to mill have a deviation of 1mm, regardless of the toolpath. No matter if inner or outer track.
My assumption is that this could possibly be caused by Vectric, but the colleagues have not really been able to help me with my problem. The test files I sent were exactly correct. The colleagues at Stepcraft are also eager to help me, but so far noch idea about the rootcause of the prob.
I received a file from a friend in which the toolpaths were written with Estlcam. A simple 50mmx50mm cube. It was also milled with an accuracy of 49.7mm (as good as I could measure). This could indicate,. Vectric could be the problem, maybe.

Maybe there is someone in this forum who had the same problem and found a -probably quite simple- solution?
I`ll attache to this post a testfile which I create out of vectric for UCCNC.

It is a simple cube of 40mm. 1x inner toolpath; 1x outer toolpath. Maybe someone will use this in a free minute and check if the cube is 39mm or even worse, or in best case it is also 40mm nach dem Fräsen.

The g-code is for 3.175mm / 5mm deep. But if sombody would help then I`ll also send a g-code with all other parameters you need.

Or maybe sombody will send me a g-code for a simple cube 40mm or 50mm which works at his setup acurat, and I`ll test it on my side.

3mm; 3,175mm; 6mm Those are the mills which I have available.

Thanks my friends your support is very much appericated.
Tobias