The issue as described is expected. The style generated by the Create Vector Tile Package tool looks correct for the stops authored with scale-based sizing enabled in ArcGIS Pro. Note that the scales used are 1:100 million, 1:20 million, 1:5 million and 1:1 million. These scales will be translated to Web Mercator Auxiliary Sphere as 8.21, 5.89, 3.89 and 1.56.
The linear size values for line widths are converted to pixels from points. (pts * 1.333 for pixel values)
If there is any additional issue that we are missing, please reach out to Esri Support to report it.