Sentinel-1 EW HV Geolocation-Grid Problem

Hello everyone, I encountered a particularly difficult problem when geocoding Sentinel-1 images.
I want to add corresponding geographic information to the image by Geolocation-Grid, such as latitude and longitude. But the final result shows that the image is very deformed.

This is the name of my product:S1A_EW_GRDM_1SDH_20180719T072036_20180719T072140_022860_027A98_C108.
My workflow is GRD border noise removal, Thermal noise removal, Speckle filtering, Radiometric calibration, and Geolocation-Grid. No problem in the first four steps, but the image will be distorted by Geolocation-Grid.
Does anyone know what the reason is? Can someone help me?