What can happen when you follow a SATNAV

There I was, minding my own business, following the SATNAV to Siguenza when we encountered upon some roads that where not yet made.  I am used to the SATNAV not knowing about new roads and taking one along old routes but this is the first time that I have ended up on a roundabout still under construction.  Worse still, Paula & Nigel were following us in our Polo!