I have a filegeodatabase containinig a dataset and some featureclasses. The dataset is originally created with the spatial reference ETRS 1989 UTM Zone 32N.
One of the features in the add-in is to change the spatial reference of this dataset based on some values from a list. The code runs the "Define Projection" tool and the dataset is being updated with the new spatial reference. ETRS 1989 UTM Zone 32N to ETRS 1989 UTRM Zone 33N (or 35N).
When I try to get the spatial reference of one of the featureclasses through ArcGIS Pro SDK:
await QueuedTask.Run(() =>
{
using (Geodatabase geodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(uri)))
using (FeatureClass featureClass = geodatabase.OpenDataset<FeatureClass>("JSRGrensepunkt"))
{
var featureclassDefinition = featureClass.GetDefinition();
var sr = featureclassDefinition.GetSpatialReference();
/* more code ...*/
});GetSpatialReference() returns the original spatial reference (32N) and not the current one (33N):

If I look at the same featureclass in ArcGIS Pro, I can see that the featureclass indeed is in 33N:

What might be wrong here?