Inverse Kinematics locks ignored Here is a very simple leg.

Leg.lower.L has an ik constraint applied, of chain length 2.

Foot.L has no ik applied but copies its rotation from IK_Foot.L
As discussed here here  this enables the Inverse Kinematics fields of Leg.lower.L &amp; Leg.upper.L
I want to limit the rotations of the upper leg hat may be caused by ik. To test the extreme case, suppose I attempt to prohibit rotations of Leg.upper.L completely. I have applied Lock IK for X, Y &amp; Z.

However, as you can see, those locks are ignored.

Why are the locks having no effect?
Blender v2.83.0 on Linux
A Pole Target interferes or takes president over the Inverse Kinematics constraining in the Bone Properties tab for the last bone in the chain.
Some info here and (more or less accurate info with a bunch of links) here
I think that sadly there aren't any (easy) workarounds. Non that I'm aware of in any case.