If you download the Third Person Controller in the Unity Starter Assets and then click the “Setup Rig” button on the PlayerArmature, the running animation will wobble around the lower spine bone.
This wobble occurs regardless of the Rig Builder containing any Rig Layers. As soon as you disable the Rig Builder, the animation defaults.
Did you ever figure this out? I believe I am hitting the same issue. What unity version are you on? I am fine on 2022.2.0a10 and below. I’ve tried 2022.2.0a13, 2022.2.0a16, 2022.2.0a17 and most recently 2022.2.0b1, but no luck.
I am using animation rigging 1.2.0 no problem in 2022.2.0a10.