Problem on chain of bones

Hello everyone, this is my first discussion.

I created a chain of bones with an IK. It should simulate a queue. The problem is that at some point of the rotation by IK, the chain undergoes a position inversion. Bone.16 is the IK of Bone.15 (clearer) and has no “parent”, as opposed to all other bones that are linked in sequence.

comes up to this position without problems


then shoot in this position


This also happens during an animation in which I set a starting position and an arrival position. Is it my mistake or a blender problem? Can it be corrected or avoided?

Here is the video that shows the steps to create the tail and highlight the problem.

Thank you