ActiveRecord::RecordInvalid: Validation failed: Validate approvals before merge Number of approvals must be at least that of a...

https://sentry.gitlab.net/gitlab/gitlabcom/issues/677642/

ActiveRecord::RecordInvalid: Validation failed: Validate approvals before merge Number of approvals must be at least that of approvals on the target project
  active_record/validations.rb:78:in `raise_validation_error'
    raise(RecordInvalid.new(self))
  active_record/validations.rb:50:in `save!'
    perform_validations(options) ? super : raise_validation_error
  active_record/attribute_methods/dirty.rb:30:in `save!'
    super.tap do
  active_record/transactions.rb:324:in `block in save!'
    with_transaction_returning_status { super }
  active_record/transactions.rb:395:in `block in with_transaction_returning_status'
    status = yield
...
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ActiveRecord::RecordInvalid: Validation failed: Validate approvals before merge Number of approvals must be at least that of approvals on the target project