I don't know if this is a bug per se -- two things are happening, you are transitioning from digital zoom on one lens to optical on the next. And you are changing from a lens in one position to a lens that is slightly shifted in space (different location on the back of the phone). For a long range target, this will be almost negligible (distance between cameras << distance between lenses). When close up as you show in your video, however, it's more obvious and annoying.
Speaking to Apple Engineers ?
So, this is something to report to Apple support more than on this forum.