I bought my MY2014 3.0CRD recently at 34 000 km (I live in Belgium).
The first owner had it serviced before the sales (12/2016) and S49 recall was applied.
I had a similar fan behavior twice, without any overtemp or excessive engine load.
I read somewhere else that it happened after S49 recall, and that an update of the S49 is available.
I did not go to the dealer yet, but I'll ask them next time ...
Cooling fan mystery