Earlier quoted context omitted.
Why would it raise a warning flag? I'd move to Australia for a one-week job, but I would hate moving to another town for six months. [I'm in Europe.] I just can't see any drawback to short-term contracts.
Certainly in my experience, all my contracts have been a minimum of 3 months, but averaging around a year and going up to a couple years or even more if you include return contracts. Its not necessarily the length, but the lack of extensions that is a warning sign. Most projects do not last a short time so a lack of extensions indicates a problem.
I am really biased towards short, "solvable" projects :)