The Find Existing Locations analysis tool in ArcGIS Online Map Viewer Classic does not properly include all features within a polygon boundary when using the "Completely Within" expression.
Non-reproducible when tested with ArcGIS Online Spring 2022 release (v10.1).
解决办法
Use ArcGIS Pro:
Add boundary and data layers to the map in ArcGIS Pro.
Click Select by Location. For Input Feature select BUG_000144751_SampleData2. For Relationship select 'completely within'. For Selecting Features select BUG_000144751_Boundary2.
Click Apply.
Right-click BUG_000144751_SampleData2 > Selection > Make Layer from Selected Features.