Windows 10 x64 v1909.

In previous versions of Illustrator (up to v23.1), Save to Web would work correctly even when a file had multiple artboards. However in v 24x; the Save for Web is adding additional pixels around the image even when the artboard selected does not have additional space.

I have attached two screengrabs of the same file, one using AI2019 (correct)_ and the other using AI2020. In both cases the identical artboard is selected and same settings applied.

Further, if the 'crop to artboard' option is checked, then an additional line of transparent pixels appears in the outputted PNG which is not there in the original artwork. Again two example screengrabs are attached to demonstrate this, along with the PNG files generated from the different Illustrator versions.