You must close Pro and re-open, then create a new map document, add the PostgreSQL featureclass to a new map and see if it displays fine this time.
You can also try to copy the PostgreSQL Featureclass to a file geodatabase, then check if the data displays fine from the file geodatabase, then copy the featureclass from the file geodatabase into the PostgreSQL geodatabase and see if the data displays fine, don't forget to close/open Pro. You cannot disconnect from the PostgreSQL geodatabase in Pro, this ArcMap feature is not available in Pro yet, and the Pro refresh option might not work as you expect therefore close/open Pro again to make sure the connection to the PostgreSQL geodatabase is refreshed properly.
This will help to narrow down where the problem might be and if the existing PostgreSQL Featureclass that does not display the data has any other issue.
Also, check the coordinates system properties, resolution and domain extent (max / min x,y boundary), you might have features beyond the extent and that needs to be adjusted, either delete those features or change the featureclass extent, this is known to cause issues to draw the featureclass data even when you have a valid spatial index created.
Recalculate Feature Class Extent (Data Management)—ArcMap | Documentation (arcgis.com)
| Marcelo Marques | Principal Product Engineer | Esri |
| Cloud & Database Administrator | OCP - Oracle Certified Professional |
I work with Enterprise Geodatabases since 1997.
“ I do not fear computers. I fear the lack of them." Isaac Isimov