Strange error associated with imported .blend file

It's no secret. Importing blend files into Unity is annoying. T$$anonymous$$s time, the fbx import was not carrying over all the animations, so I had no choice but to import the .blend file directly. Everyt$$anonymous$$ng seemed to be going ok until I set up the model, pressed play, and got the following error four times:

NullReferenceException: (null) UnityEditor.SerializedObject..ctor (UnityEngine.Object[] objs) (at C:/buildslave/unity/build/artifacts/generated/common/editor/SerializedPropertyBindings.gen.cs:72) UnityEditor.AssetImporterInspector.GetSerializedObjectInternal () (at C:/buildslave/unity/build/Editor/Mono/ImportSettings/AssetImporterInspector.cs:57) UnityEditor.Editor.get_serializedObject () (at C:/buildslave/unity/build/artifacts/generated/common/editor/EditorBindings.gen.cs:144) UnityEditor.ModelImporterClipEditor.OnEnable () (at C:/buildslave/unity/build/Editor/Mono/ImportSettings/ModelImporterClipEditor.cs:128)

It doesn't seem to affect the game in any way, but it's a complete mystery to me. Pasting the error into google didn't get me very far.

*Edit: I reloaded and its seems to be ok now, but it would still be good to know what the error meant and/or how I can avoid it in the future.