Why does the sequelize id auto-increment even without adding the data?

Question

Hello, I have a table that has[id, user, password, level] following these settings:

 id: {
   type:sequelize.INTEGER,
   primaryKey: true,
   autoIncrement: true,
   allowNull: false
 },
 user: {
   type: sequelize.STRING,
   allowNull: false,
   unique: true
 },
 password: {
   type: sequelize.TEXT,
   allowNull: false

 },
 level: {
   type: sequelize.STRING,
   allowNull: false
 }
})

Whenever I try to create a new user and it already exists, returns the error "Sequelizeuniqueconstrainainterror" , until then everything ok, because I had configured it, as shown in the code above. However, when I create a new user without returning this error, the "id" of the new user , in the database, appears as if the previous attempt had worked, example:

-I gave several clicks on the creation of a new user with the same name and returned several errors, however, after successfully creating a new one, the id was in this numbering.

13  william1    william15   admin
14  william william15   admin
34  willia  william15   admin
59  will    william15   admin

Code creating a new user:

rCreateUser.post('/', async (req: Request, res:Response)=> {
  const {user, password, level} = req.body
  try{
    const creatingUser: Model<any, any> = await Credencial_model.create({
      user:user,
      password:password,
      level: level
    })
    
    return res.json(creatingUser)
  }catch( Err) {
    console.log(Err.name)
    if(Err.name === 'SequelizeUniqueConstraintError'){
      res.status(409).json({info:'usuario já existe', error:true})
    }
  }
})