Model.build strips off timestamps

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What you are doing?

Post a minimal code sample that reproduces the issue, including models and associations

console.log(instance.dataValues, instance.toJSON(), Model.build(instance.toJSON()));

What do you expect to happen?

The fields should be identical in all 3 cases. The instance is a freshly selected row out of the database. No updates have occurred.

What is actually happening?

After passing instance.toJSON() into Model.build, the new returned instance does not contain createdAt or updatedAt timestamps. I am manually adding these stamps, and am not using the timestamps option.

Dialect: postgres
Database version: 9
Sequelize version: 3.30

Start with the JavaScript reproduction in the issue and inspect the Model.build path, comparing instance.dataValues, instance.toJSON(), and Model.build(instance.toJSON()). Confirm the behavior with manually supplied createdAt and updatedAt values when the timestamps option is not used; done means the built instance retains both fields.