On RHUI 2.1, after updating pulp packages pulp-migrate command failed with error "model validation failure in Package for model xxx field size is not present"

Issue

• On RHUI 2.1, after updating pulp packages pulp-migrate command failed with error "model validation failure in Package for model xxx field size is not present"

# pulp-migrate
removing persisted tasks
20 errors on validation, see /var/log/pulp/db.log for details

# cat db.log 
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field size is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field license is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field vendor is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field repo_defined is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field buildhost is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field requires is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field download_url is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field provides is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field group is not present
model validation failure in Package for model dfa9c66b-5370-48ec-bdfe-6ae903200927: field description is not present