Windows 7 64-bit
Short description of error
Both "Inverse Kinematics" bone constraint and AutoIK ignore bone rotation limits.
Exact steps for others to reproduce the error
Rotate the bone manually, and z rotation will only go from 0 to 90, but turn on AutoIK and it will ignore the rotation limits. The same will occur if you unhide the Inverse Kinematics bone constraint that I added, then move the Circle toward the hips.