Why isn't my scriptable object storing correctly in the AssetBundle?

I want to make AssetBundles which include two textures and two colours. The colours are stored in a custom C# class declared as follows:

 public class PaintInfo : ScriptableObject
 {
     public Color primary;
     public Color secondary;
 }

while the C# code used to build the bundle looks like this (with diffuseTex and specularTex both being Texture2D objects). The colours are hard-coded for now, but will eventually be sourced from elsewhere.

     diffuseTex.name = "Diffuse";
     specularTex.name = "Specular";
 
     string outputName = "TEST.UNITY3D"
 
     PaintInfo newPaintInfo = ScriptableObject.CreateInstance<PaintInfo>();
     newPaintInfo.name = "PaintInfo";
     newPaintInfo.primary = new Color(1.0f, 1.0f, 0.0f, 1.0f);
     newPaintInfo.secondary = new Color(1.0f, 0.0f, 0.0f, 1.0f);
                 
     // save the asset to be able to put it in the asset bundle
     string assetName = "TEST_PAINTINFO.ASSET";
     AssetDatabase.DeleteAsset(assetName);
     AssetDatabase.CreateAsset(newPaintInfo, assetName);
     AssetDatabase.SaveAssets();
     List<UnityEngine.Object> texList = new List<UnityEngine.Object>(EditorUtility.CollectDependencies(new UnityEngine.Object[] { newPaintInfo }));
     texList.Add(diffuseTex);
     texList.Add(specularTex);
 
     bool buildOk = BuildPipeline.BuildAssetBundle(null, texList.ToArray(), outputName, BuildAssetBundleOptions.CollectDependencies);
 
     if (buildOk)
     {
             logFile.WriteLine("# Bundle created ok");
     }
     else
     {
             logFile.WriteLine("# Error: Bundle not created");
     }

When I load in the asset bundle in the game code, the two textures are correctly present, but instead of the PaintInfo object, I have a TextAsset whose name and text fields are both empty strings. What am I doing wrong?