Not familiar with your car/engine but, wait & see if it does it again.
If you have a vacuum operated EGR, yes it may have had some accumulated moisture that froze in the line.
I remember years ago Chrysler had a terrible time with moisture freezing in the line to the MAP sensor.
When they re-located the sensor to the inside of the vehicles, the problem was solved.
Worst time of the year for moisture related problems is when the temperature bounces cold/mild.
