Plot_city_state central plane not drawn behind all positive columns

[dime10]

Information

• Qiskit Terra version: 0.10.0
• Python version: 3.7.4
• Operating system: Windows 10

What is the current behavior?

As seen in this image, the plane at z=0 is drawn in front of some of the positive columns. Surprisingly most, but not all, of the columns are drawn this way.

Other examples:

Steps to reproduce the problem

Plot a state vector with positive amplitudes.

What is the expected behavior?

Positive columns (z>0) should be drawn in front of the plane, negative columns behind it (this second part seems to work already).

Suggested solutions

Don't know what is causing this.

[mrvee-qC]

Update for Santa - QGoGP

✅ Issue still reproducible as per original author. Any plot with positive and negative columns should reproduce the issue. Example code to reproduce first image:

from qiskit.tools.visualization import plot_state_city
plot_state_city([0.5+0.5j , 0.5 +0.5j ,0.5 +0.5j ,-0.5-0.5j],
     title="Ghosts from qiskit past")

Not sure if the right section but it seems to completely mess up for different states! (State vectors are on top of the ss)

Anomaly 1 - Statevector [0.191 + 0.462j , 0.191 + 0.462.j , -0.191 + 0.462j , -0.191 + 0.462j]

Anomaly 2 - Statevector [0.354 + 0.354j , 0.5 + 0.j , 0.354 + 0.354j , 0.5 + 0.j]

Will update comment/add more comments if cause is found/fixed.

Python version 3.9.7
qiskit-terra version: 0.19.1

[AlexanderGroeger]

I'm already working on the other mentioned issue. I could easily tack this on to my work changes. Would someone please assign this task to me?