Edge does not always reflect a label and position it offset

[rat-h]

I want to use diagrams to automatically draw models of a brain network. I need to cluster different parts and label connections with connection weight and delay. However, edges not always show labels and if they show the position of the label is somewhat off.

Here a minimal

from diagrams import Diagram, Cluster, Edge
from diagrams.custom import Custom



nodes=['P', 'I', 'T', 'R']
connections=[
    ['T', 'P', 0.07215613318258902 , 3.000411809536968],
    ['P', 'T', 0.04542521977383042 , 3.000411809536968],
    ['P', 'R', 0.028688428150340634, 3.000411809536968],
    ['P', 'I', 0.20226356207694524 , 4.606920945687344],
    ['I', 'P', 6.781459088887569   , 0.9380132322853566],
    ['P', 'P', 0.003704263180325445, -0.1],
    ['R', 'T', 0.3439813519108478  , 5.132116246577708]
]
gnodes={}
with Diagram(f"Model ", 
    show=False, filename=f"diagramtest", 
    outformat=["jpg", "png", "svg"],
    direction="LR"):
    with Cluster("Cortex",direction="TB"):
        for n in list('PIE'):
            if n in nodes:
                gnodes[n] = Custom(n,f'tmp/{n}.png',imagescale="false")
    with Cluster("Thalamus",direction="TB"):
        for n in list('RT'):
            if n in nodes:
                gnodes[n] = Custom(n,f'tmp/{n}.png',imagescale="false")
    for f,t,w,d in connections:
        gnodes[f] >> Edge(label=f'{w:0.3g} {d:0.3g}') >> gnodes[t]

On the diagram connection from P to R and from P to itself doesnot have lables. The over labels are offset quite alot.