MDD playback and invisible keyframes / blend file(s) attached/ exporting non-armature deformations

Snake MDD test 210424a.blend (2.5 MB)
Snake FBX test 210420b.mdd (2.0 MB)

I’ve been experimenting with the MDD export function. To use this addon, enable the NewTek (wOoT!!!) MDD Format addon. This adds a export function to your File/Export menu. This exports any (?) mesh deformation, whether it be by armatures or Modifiers such as Lattice or Wave.

I made a Curve conforming snake animation, and used the MDD addon to export the deformations. Then I made a FULL COPY* of the snake animation Scene, deleted the CURVE modifier and the curve it referenced in this new Scene (but within the same Blend file), and applied the MESHCACHE modifier to the “snake” mesh/object.

Here’s the question: While I could see that this had a deformation effect, there was also keyframing channels from the original mesh, the same Y translation that caused the mesh to animate along the Curve. That is, the deforming mesh also was translating along the Y axis because the original mesh had Y translation. BUT, and here’s the important bit, I couldn’t access/see the keyframes, I could see only the initial keyframe, but the deforming mesh moved along the Y axis as if there were multiple keyframes.

(Hopefully this is true of the sample provided above. I also included the MDD file in case there were path dependencies on my systems that made it non-portable. *Making a copy in Blender seems fraught because IME it often links things that I usually don’t want to be linked. That’s why I made a FULL COPY, hoping it would be truly independent.)

It’s possible, in this case, to simply delete the ONE offending keyframe, but why is the Object transforming at all when there’s only one keyframe??? And I know it’s the object because its origin is moving, ie, it’s not solely deformation.