There ois a mesh check addon in blender that allows you to check all mesh for faults and it will highlight in color what polygons have issues, try that to make sure all polys are good to go before export from blender. In blender select your avatar mesh in the edit mode and re-apply normals to make sure they are not flipped > then export. What happens if the avatar model normals are flipped is that clothing tries to simulate to the inside the avatar, but is obstructed by the mesh, so it can get a sucked in simulation effect as you activate simulation and goes to the floor. You may also need to change the DAZ units and swizzle orientations on import & export. You can create a data exchange preset in Blender for both the import from DAZ and the export preset to CLO3D, so set this default once with the parameters your want and name it save it to your Blender presets list so you can use that import.export setup repeatedly using that saved preset. When you export from DAZ to blender ensure the model has any attributes and scales set correctly, (there is a blender to DAZ bridge that might be a better choice for interpolation) that all material shaders (PBR node graphs with texture materials are correct and that any 16/24bit materials are downgraded to 8bit for use in CLO3D) and that all poly surfaces normals do not have any scalar issues.

You can see that they are greyed out, which means the export process has a fault from Blender. Copy the dzblenderbridge. Check the normals on your avatar are not flipped on import > export from blender for that DAZ model. Download and unzip the dzblenderbridge.dll file.

Import daz to blender