Think you set only keyframes on the part but you should also have on camera. Also maybe auto keyframe is enabled that generates new keyframes when you make a movement!
Next on each keyframe you have some in/out transitions that you can control. Think standard is set to smooth. Thats why you have slight movement between each of them. Select a keyframe and on right side you will see the properties. Select on first keyframe "hold" for Out and when you duplicate it just switch so that "hold" is In for transition. That way you can keep it stable without any movement.
I had not even seen that menu, and it solved my issue right away. Thank you so much for your help Husein.