That's really interesting, I hadn't sliced it that way yet.

I know FiveThirtyEight allocates undecideds evenly - if 8% respond undecided they assume 4% will break Biden and 4% will break Trump. In one of the podcasts they discussed this assumption and it's what they have found to be the most accurate historically.

We might be seeing a shift towards that no longer being true - maybe 75% break red and 25% break blue now.

Edit: Also, It looks like Jorgensen (Libertarian) significantly underperformed her polling (~3% > ~1%) in the first few states I spot checked. If those voters broke for Trump, that makes up about 2% of the error. That'd take a lot more in depth checking though.