While the issue is reproducible in ArcGIS Pro 3.0.3 and also for the Pairwise Dissolve tool, the issue is not reproducible in ArcGIS Pro 3.1_41807. If the issue persists, contact Esri Support Service.
解决办法
To convert the output of the Dissolve (Data Management) tool back into the custom precision and scale, add a field with the data type double (12,0).
Run the Field Calculator with a calculation where the new field equals the old field.