Hi,
This looks strange and should not happen. How many processes did you run with? I was unable to reproduce the error, with a slightly modified script. Perhaps try to run with fewer processes. Also, I noticed that your k-point sampling for the ElectronPhononCoupling is around the Gamma-point (ka_range=[-0.1, 0.1], kb_range=[-0.1, 0.1]), while I guess you would rather have it around the K-point, i.e.
kpoints = RegularKpointGrid(
ka_range=[0.23, 0.43],
kb_range=[0.23, 0.43],
kc_range=[0.0, 0.0],
na=20,
nb=20,
nc=1,
)
Regards,
Troels