Flipping keyframes in walk cycle animation not working I try to flip my keyframes like in this tutorial.

I do everything exactly like in the video, but it fails.






Select all bones from armature.
Set timeline frame to 80
Select all keyframes from frame 1
Click on 
Click on 




Result:



What am I doing wrong? I just try to flip the keyframes like in the video.
The bones are named with the naming convention name.L and name.R.

I was already reading many same questions, but there is no working solution.
Something weird is going on, but you can solve it by selecting in edit mode all the .L bones, delete them, then select all the .R bones, Shift+D to duplicate, Esc not to move them, Shift+C set the cursor to center, make the cursor pivot point, Ctrl+M  X to mirror the bones on the X axis, Then Armature - Flip Names.

Everything now works as expected.

The reverse (L-R) of this whole operation doesn't work!