It looks like (some of) the ends of the splines are joining the end elipses at a tangent to the plane of the elipse.
I dont do much 3D but 2D splines ask for the tangent to the endpoints when you are creating them.
I would suggest that this is a setting that you had set before which is no longer set now you have had to reload Autocad.
Try checking your help and see what options are given for startpoint and endpoint tangent settings.
Im intelligent enough to know that I dont know everything; but I'll tell you all about it anyway.