node positions do not work with link value zero in Sankey

Hello,
I'm new to the plot.ly lib but I already discovered an issue.
If there is a node with:

• no links
• only links with the value of zero

the manual positioning doesn't work anymore except if you delete the relating coordinates of this node and keep the node in the list (see third example).

Below you can find a short testing code with the generated output.

working example

import plotly.graph_objects as go
data=go.Sankey(
    arrangement = "freeform",
    node = {
        "label": ["A", "B", "C", "D", "E", "F"],
        "x": [0.2, 0.1, 0.9, 0.7, 0.3, 0.9],
        "y": [0.1, 0.9, 0.2, 0.1, 0.9, 0.9],
        'pad':100},  # 10 Pixels 
    link = {
        "source": [0, 0, 1, 4, 4, 3, 3],
        "target": [1, 3, 4, 3, 5, 2, 5],
        "value": [3, 3, 5, 4, 10, 1, 7 ]})
fig_sankey = go.Figure(data=data)
fig_sankey.show()

node with only one link with value of zero

import plotly.graph_objects as go
data=go.Sankey(
    arrangement = "freeform",
    node = {
        "label": ["A", "B", "C", "D", "E", "F"],
        "x": [0.2, 0.1, 0.9, 0.7, 0.3, 0.9],
        "y": [0.1, 0.9, 0.2, 0.1, 0.9, 0.9],
        'pad':100},  # 10 Pixels 
    link = {
        "source": [0, 0, 1, 4, 4, 3, 3],
        "target": [1, 3, 4, 3, 5, 2, 5],
        "value": [3, 3, 5, 4, 10, 0, 7 ]})
fig_sankey = go.Figure(data=data)
fig_sankey.show()

kind of working again cause coordinates of C are deleted

import plotly.graph_objects as go
data=go.Sankey(
    arrangement = "freeform",
    node = {
        "label": ["A", "B", "C", "D", "E", "F"],
        "x": [0.2, 0.1, 0.7, 0.3, 0.9],
        "y": [0.1, 0.9, 0.1, 0.9, 0.9],
        'pad':100},  # 10 Pixels 
    link = {
        "source": [0, 0, 1, 4, 4, 3, 3],
        "target": [1, 3, 4, 3, 5, 2, 5],
        "value": [3, 3, 5, 4, 10, 0, 7 ]})
fig_sankey = go.Figure(data=data)
fig_sankey.show()

Inizia eseguendo gli esempi Sankey Python forniti e confrontando il posizionamento libero quando un collegamento ha valore zero. Traccia il percorso di rendering Sankey dalla definizione della figura Python fino al componente che gestisce le posizioni dei nodi. Il lavoro è completato quando le coordinate manuali rimangono effettive per i nodi senza collegamenti o con soli collegamenti di valore zero, con un test di regressione che copra entrambi i casi.