Not just Le Pen and Hofer; according to this tweet by Nate Silver, this is the sixth European election in a row where the nationalist candidate under-performed their poll numbers.
Yeah, nationalist candidate just create more unpredictability, but there is no such thng as permanent nationalist-bias in the polls. The problem is treating 3-point lead as an assured win, while it is not. I personally think Nate Silver is doing a very good job and analysed US election very well.
Macron 59.8-40.2 Le Pen as we edge to 30%. Marine about to drop to 30s any time soon.