Sentinel-1 Terrain flattening output error

I am pre-processing a number of Sentinel-1 EW GRDM images over northeast Greenland and am running into issues with the terrain-flattening part of my pre-processing. My steps are as follows:

  1. Calibrate to beta0
  2. Terrain flatten
  3. Terrain correct
  4. Resample

For a number of the scenes the terrain-flattening works completely fine, however, for several, the output is almost entirely empty aside from a few artifacts.

Some troubleshooting attempted so far has included processing images individually as opposed to in a batch, terrain-flattening on non-subsetted images as opposed to subsetted ones, and using different DEMs (Copernicus Global DEM 30 and an external DEM - AW3D30). All to no avail.

A couple of scenes that fail during terrain flattening include the following: