sequelize-typescript: Alias cannot be inferred

Given the following models, each of the associations work fine in isolation but not if used together. I’m getting:

Error: Alias cannot be inferred: “Estimate” has multiple relations with “Employee”

What am I doing wrong?

@Table()
export default class Estimate extends Model<Estimate> {

  // Fields....

  @ForeignKey(() => Employee) @Column estimatorId: number;
  @BelongsTo(() => Employee) estimator: Employee;

  @ForeignKey(() => Employee) @Column foremanId: number;
  @BelongsTo(() => Employee) foreman: Employee;

  @BelongsToMany(() => Employee, () => Crew) crew: Employee[];
}

@Table()
export default class Employee extends Model<Employee> {

  // Fields....

  @HasMany(() => Estimate, 'estimatorId') estimatesAsEstimator: Estimate[];
  @HasMany(() => Estimate, 'foremanId') estimatesAsForeman: Estimate[];

  @BelongsToMany(() => Estimate, () => Crew) estimatesAsCrew: Estimate[];
}

@Table()
export default class Crew extends Model<Crew> {

  @ForeignKey(() => Employee) @Column employeeId: number;
  @ForeignKey(() => Estimate) @Column estimateId: number;

}