Can I leave earlier than the duration of my German National Visa (also known as long-term visa or D visa)

I have been invited to be a guest scientific researcher in a well known German institute. So I am applying for a German National D visa for 10 months which is the length of my contract. But I expect to get a job offer to work in a different country and may have to leave prematurely (say after 2 months).

Can there be an issue in future? For example, they might ask why I applied for such a long-term visa when I didn't have plans to stay as long.

This post has been updated to provide more context