If I disable "Save Record Assets", all animations are recorded.
I have checked the implementation of bSaveRecordedAssets, but I am not sure if this is the intended implementation.
1. Open "TakeRecorder_test_Pawn.umap"
2. Add a Source of "All Nearby Spawned Actors" to TakeRecorder.
3. Add the Source of "Level Sequence" to TakeRecorder and specify the Level Sequence of "「TakeRecorder_Skeletal".
4. Activate the "Save Record Assets" option.
5. Start PIE and press the Record button of TakeRecorder.
6. When TakeRecorder_Pawn finishes playing, finish recording and exit PIE.
7. If you check the animations saved in the Cinematics folder, you will see that no animations are recorded except for the first frame.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-120083 in the post.