Hi Peer, maybe I have misunderstood what you are actually asking about since you are referring to tangents and not just the widths of the fillets.

But in the case you have here it's also normal that the fillet pieces are not tangent to each other because you are keeping this edge of the model to be sharp:



Fillet surfaces will not be tangent where they touch each other across a sharp edge like that, that's just a normal result for fillets. They will be both not tangent to each other and not the same width as well.

- Michael