thank you, Alexander, for trying to be more precise.
I don't know a contour tool, but guess you mean the Paths tool
and face a similar behavior here.
My solution for you is to enter the Design mode.
You can drag the nodes around there as you desire.
To me it looks like you re-translated the texts back to English.
Sometimes I make the same mistake. To avoid confusion please
switch to the English language before reporting messages in public.
You find in the Preferences dialog in the Interface panel.
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