That’s fairly common in Aizu (or Fukushima? Tohoku?? It’s hard to know how localized various parts of the dialect are here) as well. People also drop the last う syllable in almost any verb before の.
For example 出るの？→出んの？ 走るの→走んの？受けるんだ。→受けんだ
This threw me for a loop for a good while until someone pointed it out to me.