I've also encountered this issue...I am able to use SetParameter using GetMorphID, but keyframes do not get created on the morphs. Not sure what the issue is.

I've also tried using tag.GetCTracks, and iterating through the resulting list. This seems to let me set the keyframes, but just sets the strength of all keyframes to 0, not the actual value I am passing.

        morph_tracks = morph_tag.GetCTracks()
        for track in morph_tracks:
            morph_tag.ExitEdit(doc, True)
            create_key(track.GetCurve(), get_current_time(), 0.5, c4d.CINTERPOLATION_STEP)
            morph_tag.UpdateMorphs()

I would expect the above to set all morphs to a strength value of 50%, but they all are just 0%.

This is using the same CreateKey function from here: https://github.com/PluginCafe/cinema4d_py_sdk_extended/blob/master/scripts/04_3d_concepts/scene_elements/animation/ctrack_create_keys_r13.py

Would anyone happen to have context on how to set these keyframes???