Lightroom Classic auto upon import vs auto after import

One issue is that when you apply Auto Settings to more than one photo at a time (via Import, Quick Develop > Auto, or a preset), LR uses reduced-resolution versions of the photos to make Auto go faster. Usually, there's no difference between applying Auto to the full- and reduced-resolution versions, but on at least 6% of the photos, there are visually significant differences.

After applying Auto to a photo in batch and then go to the photo in Develop, if the Auto button is not greyed out, that means that the batch version of Auto has produced different settings than if you click Auto in Develop.  Click the Auto button to get the full-resolution "real" settings.

See here for a feature request for an option to always use full-resolution versions in batch Auto (which Adobe has ignored):

https://community.adobe.com/t5/lightroom-classic-ideas/p-option-to-batch-apply-auto-settings-with-full-resolution-image-data/idi-p/12248496

On modern computers, Auto is fast enough that many users would prefer to just always use the "real" Auto and wait a little longer for the batch operations to complete.