Couple issues I observed, both of which are incorrectly shown on Google Maps but are correct on OSM:
UT 13 is shown on an old alignment between the current UT83 and 4800W_S waypoints. Instead of taking that shortcut to Corinne, 13 goes directly south to 83 before turning east. The east end of UT 83 would need to be slightly truncated as well.
Also, the north end of UT 82 is incorrect. Instead of proceeding east on Factory Street all the way to 13, it turns north on 5400 West.
I noticed the UT 13 / UT 83 thing as well and you beat me to saying it. To be sure, we drove along the Corinne Cutoff through town as well as along the main sides labeled UT 13 and UT 83 to be sure. The cutoff is even 25 mph along part of it. And I may be mis-remembering, but it looked like a lower quality road. The GSV from 2013 show a center line, but I don't remember that. The satellite view doesn't show those lines either. Maybe they downgraded it in the last few years. There's a big gas station where 13 and 83 are T-ing into each other.
And I'm ticked if what you say about UT 82 is correct as I thought we'd clinched it. But, it would explain a lot. I was driving us north on UT 13 and saw a sign for To UT 82. There was a small exit as they were grade separated. OSM has that labeled West 12800 North. Turned left and continued straight into what gets labeled Factory Street in town. I also didn't see a sign at the four-way stop at Main Street for UT 82 turning. Continued through it until it didn't look right and checked Google Maps on my wife's phone before turning around and then continuing towards UT 102. Then, later that day, we went up to I-15 Exit 392 and came back south on UT 13. I saw the sign for UT 82 as UT 13 starts curving around. I thought that maybe it was just a really long off ramp. We continued on UT 13 as we were trying to finish that section. If I had realized its location was questionable, I would have come back around and "circled the block" like we did in Corinne.
So, US 89, were you in northern Utah for the Spike 150 celebration as well?
Mike