thank You and thank to All.
Not only the line was wrongly counted.
Going from DFT without SOC to SOC, we changed
the pseudopotentials, and Pb is now without d-states
(before it was with d-states). So we have 40 electrons
and not 50 electrons in the cell. This is why so small
gap between 50 and 51.
We start with yambo. When someone expects that
something will go wrong, he/she usually generates the
nonexisting problems.
We will be more careful with parameters and more confident
with yambo now
Best regards,
Gosia