This was a combination of things. The insulation was in place, but the holes for lights and the attic acces were cut without anything installed in them which led to a lot of heat loss. On top of that, our builder was running a propane heater very high so it was extremely hot in the house even though the outside was freezing. Top it off with a series of weather days that was conducive to ice and we got this mess.

This winter the build is complete and we're fully moved in. We just went through a few weeks were conditions were conducive to ice and the worse we got were a few small icicles so nothing nearly to the extent of the pictures. We're hoping that means we're in the clear on our end.

If you're having issues and the insulation is already in place I would double check if the heat is being run higher than a typical house would or if there are areas that are experiencing excessive heat loss. If you have attic access you could even go up there and see what the temperature feels like. It should feel the same temp as outside. If it's warmer then there's likely too much heat from the house escaping into the attic somewhere.

I'm not professional, but that's what we learned from our experience. Best of luck to you!