Description
When the variable to predict is categorical and spatial thinning is applied, the thinning is applied by class. A feature is only thinned if there are other features of the same class within the designated threshold. Some classes may not have any features removed in the thinning process.
Solution
No action is required. If you want features to be thinned regardless of the category in the variable to predict, do not select a categorical variable as the Variable to Predict parameter value.