A common misconception ¹⁾ is that HingeJoint constrains the rotation or localRotation of the Transform that it is attached to. This is not strictly true. HingeJoint only constrains the relative rotation between its own RigidBody and the Rigidbody in the ConnectedBody field.

Another common misconception is that HingeJoint.angle and HingJoint.axis represent the rotation of the Transform that it is attached to. This is also not strictly true. That is, Quaternion.AngleAxis(hingeJoint.angle, hingeJoint.axis) does not necessarily equal hingeJoint.transform.rotation or hingeJoint.transform.localRotation.

These two misconceptions, taken together, can make a HingeJoint behave quite differently from what you might expect.

To quote the official docs:

The rest angle between the bodies is always zero at the beginning of the simulation.

The consequence of this is that HingeJoint.angle does not depend on the starting orientation of either the joint's RigidBody or the connected RigidBody. And because HingeJoint.limits represents limits on HingeJoint.angle, the limits are also independent of any starting orientation of the bodies.

An example: Consider a GameObject with rotation (0, 0, 0) and a HingeJoint on the x-axis with limits of [-90, 90]. When played as-is, this GameObject will be free to rotate between (-90, 0, 0) and (90, 0, 0). However, if you rotate this GameObject in the editor such that it starts with rotation (90, 0, 0) and play it, the GameObject will then be free to rotate between (0, 0, 0) and (180, 0, 0) - even though the angle limits have not changed.