Can't see axis-transformation curves in the graph editor for bones

Hi all! I’m using Blender 2.90.1
If I animate the default cube moving it along the z-axis, there is no problem, I see the z-transformation curve on the graph editor.
But when I animate a bone of a blender cloud model, also in the z-axis transformation, it remains flat in zero value, as if it were constantly. But as you can see in the image (left) it has a different value.

Do you know why this could be happening? happens with ALL bones.

Thanks in advance!

hello, maybe share the armature so that we can test: