Problem with rigging or Roblox's Standard Animator

So I’ve been thinking of leaning the waist a bit forward for some of the Mech’s animation (Sprinting and jumping specifically) using Studio’s built-in Roblox Animator.

But!

For some reason I can’t seem to edit the waist’s rotation at all and the white gridlines tend to change its vertical position whenever I load up a previously saved animation and undoing it simply doesn’t bring the white gridlines to its previous positions, even without editing its values to actually go up that far.

Could this be my fault on how I rigged the model or is it a bug in the Roblox Animator?
Are there any plugins I could use as an alternative to the standard Roblox Animator?

https://gyazo.com/5ed8927aa163fd493c673aaea3131a78

Mech Walk Animation
https://gyazo.com/a6fc425cefadbd91d03c45059d845035

The same Mech Walk Animation but loaded from a save in the AnimSaves inside the Model
https://gyazo.com/8b9afd8be78b52c5b45a2557a8914637

The rigged model:


This is quite confusing for me and I would take any help or suggestion I can get >>

Thaaanks~!

All I can say on this is make sure that you rig everything to the waist (since that is your torso) and then rig the waist to the HumanoidRootPart.

yis i’ve done that before already