reactionForce/GetReaction force keeps increasing

Hello,

In my game, I have an helicopter that carries different rigidbodies. The helicopter is attaching rigidbodies with a fixedJoint2D. Id like to know what force is applied by the attached rigidbody. If I put the joint.reactionForce in a public variable, I can see that, after moving around a bit, the reactionforce.y keeps increasing. I would expect to stay around 125 but it can go up to 4000!

Is there any bug with the reactionForce or I just don't know how to use it?

Thank yoou