I am encountering issues with ArcGIS Pro (2.8.1) not sorting numeric attributes correctly as shown below when Urgency_CR is sorted ascending (see snapshots 1 and 2 below). When I use the custom sort, and select ascending it sorts correctly. On further investigation, it appears that Pro is sorting on the attribute to the right of the attribute I am trying to sort on. For example in the 3rd snapshot below, I tried to sort on RoadwayElevation Ascending using the drop down and it did not work. When I opened the Custom Sort window it showed the attribute to the right being sorted (I had not previously sorted on that attribute).
I have also had an issue where I was not able to sort an attribute (ascending and descending were shaded out in the dropdown menu), but I was able to sort using custom sort.