The Apply Symbology From Layer tool does not apply the symbology successfully when used in a ModelBuilder model, then run it through the Geoprocessing pane, even though the model appears to be successful without error.
Setting the output of Apply Symbology To Layer tool as model parameter applies the symbology successfully after running using the geoprocessing tool or Model Builder.
解决办法
Open the model in editing mode and run it through the ModelBuilder tab.
Use Apply Symbology From Layer tool outside of a model.