"new text" label randomly appearing in Plotly graph

Question

I have built a graph using networkx and thereafter visualized it using plotly as described in the official guide. However, I get a random "new text" label in the graph for no apparent reason. This label doesn't appear in one particular zone of the network but it rather depends on where I am zooming (so it might appear on one part and then if I zoom another part, it will appear there).
I checked all labels (nodes or edges) but as expected there is no problem there.
I even checked for any hardcoded "new text" part in the code but everything looks fine.
What could be the issue here?

Update

Here is the code used to visualize it:

import networkx
import plotly.graph_objs as go
# set node positions
pos = nx.nx_pydot.graphviz_layout(G2)

# Nodes information
node_x = []
node_y = []
node_labels = []
for key, value in pos.items():
    x, y = value[0], value[1]
    node_x.append(x)
    node_y.append(y)
    node_labels.append(key)

# Edges information
edge_x = []
edge_y = []
edge_labels = []

for edge in G2.edges().data():
    x0, y0 = pos[edge[0]]
    x1, y1 = pos[edge[1]]
    edge_x.append(x0) 
    edge_x.append(x1)
    edge_x.append(None)
    edge_y.append(y0)
    edge_y.append(y1)
    edge_y.append(None)

    # Get the edge label
    label = [val for val in edge[2].values()]

    # Get the middle line coordinates where edge's name is added
    ax = (x0+x1)/2
    ay = (y0+y1)/2

    # Not all edges have a label
    if len(label) > 0:
        edge_labels.append((label[0], ax, ay))
    else:
        edge_labels.append((None, None, None))


# create node trace:
node_trace = go.Scatter( x=node_x, y=node_y, text = node_labels, textposition='bottom center',
                mode='markers+text', hoverinfo='text', name = 'Nodes',
                marker=dict( showscale=False,
#                 symbol='circle',
                color='cyan',
                size=15,
                line=dict(color='rgb(180,255,255)', width=1))
                       )


# create edge trace:
edge_trace = go.Scatter( x=edge_x, y=edge_y,
    mode = 'lines', line=dict(width=1, color='rgb(90, 90, 90)'),
    hoverinfo='none',)
# Annotations for edge's labels
annotations_list = [
    dict(
        x = None if label[0] == None else label[1],
        y = None if label[0] == None else label[2],
        xref = 'x',
        yref = 'y',
        text = label[0],
        showarrow=False,
        opacity=0.7,
        ax = label[1],
        ay = label[2]
    )
    for label in edge_labels
]

data = [edge_trace, node_trace]
layout = go.Layout(
                title='FOL Network Graph',
                titlefont_size=20,
                width = 700,
                height = 600,
                showlegend=False,
                plot_bgcolor="rgb(255, 255, 250)",
                hovermode='closest',
                clickmode='event+select',
                margin=dict(b=20,l=5,r=5,t=40),
                annotations=annotations_list,
                xaxis=dict(showgrid=False, zeroline=False, showticklabels=False),
                yaxis=dict(showgrid=False, zeroline=False, showticklabels=False)
)

fig = go.Figure(data=data, layout=layout)

Answer 1

Ok, so I figured this out. Just in case someone will ever stumble on this, the problem was on declaring the annotations_list variable which I actually use to specify the labels of the edges. However, as you can see from the code I am labeling only some of the edges:

x = None if label[0] == None else label[1],
y = None if label[0] == None else label[2], 

The thing that I failed to correctly set here was the actual label of the edge text = label[0] which should rather be text = "" if label[0] == None else label[0].
It looks like by default a 'new text' label will be set if the text field of the annotation is set to None.