[Answered ]-Psycopg2 duplicate key value violates unique constraint (when migrating from SQLITE to POSTGRESQL)

So reading more posts I got to this one:

https://gist.github.com/sirodoht/f598d14e9644e2d3909629a41e3522ad

After reading some of the comments I remembered that the dev team got signals creating this din_status post_save, so they are the reason of duplicate entry.

Commenting the signals involved fixed the issue.