#populist Carbon County returning to its Democrat roots by voting with the big city Democrats once again.
Seriously though why did it? IIRC correctly it was the only county in Utah that Swung R in 2016.
Something I've noticed in referendums is that formerly Democratic counties swinging to the Republicans will often still vote for the "left" position on ballot issues for years after they've flipped electorally. On Question 790 in Oklahoma, Coal County was the strongest "no" voting county, more so than even Cleveland County. The 2014 Illinois miminum wage increased fared especially well in placed like Calhoun County that are formerly Dem. Virginia's RTW vote also showed this trend.