I discovered that there are strange results with some players when importing live stats using the "Update Player Ratings Using Live Stats" function.
For example,
Jared Jones, who has been performing excellently this season in the majors, has his ratings--especially his stuff and individual pitch ratings--instead go down significantly when importing live stats.
Here is Jared Jones as of the default starting rosters:
Here are his updated stats after running the update function:
However, if we were to manually input his ratings via the Editor based on his real stats from this season, we would get the following:
Obviously I don't expect the third image to flat out be the stats he gets from the update function, but I would expect the ratings to move toward that direction, rather than in the opposite direction.