Morph Target Previewer does not refresh during Reimport

Reimporting an asset with Morph Targets does not refresh the Morph Target Previewer.
Any newly-imported Morph Targets appear to not have been imported.
Closing and reopening the Skeletal Mesh Editor refreshes the panel, populating it with the missing Morphs.

This issue can also be reproduced using the Reimport Mesh / Reimport All Meshes option on the Skeletal Mesh Toolbar.

I can successfully reproduce this issue as far back as the 4.17.2 Binary (CL 3658906); it is not, therefore, labelled a regression.

1. Import MorphTarget_MorphAnim with Import Morph Targets = False
   • Located at: Engine/Content/NotForLicensees/QA/Import_Test_Assets/FBX/MorphTargets
2. Open MorphTarget_MorphAnim in the Skeletal Mesh Editor
3. Within Import Settings > Mesh, set Import Morph Targets = True
4. Select the dropdown arrow beside Reimport Mesh
5. Select Reimport All Mesh

Workaround:

1. Close and reopen the Skeletal Mesh Editor

Result:
The Reimport process completes. Morph Target Previewer remains empty

Expected Result:
Morph Target Previewer populates with mesh Morph Targets once reimport completes.