Spring Boot scans the compiled files twice, leading to "A bean with that name has already been defined" error. How to properly solve this?

I have a rather simple "Spring Boot" project modeled after the "Tacos" example from "Spring in Action" by manning.com.

So far, I have not used Spring autowiring, but now it's time!

Here we go, absolutely nothing unexpected and the below singleton is injected with "constructor injection" at various points:

package tacos.model.ingredients;

import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;

@Component
public class IngredientRelation {

   @Bean // Indicates that a method produces a bean to be managed by the Spring container.
   @Scope("singleton")
   public static IngredientRelation ingredientRelation() {
      return new IngredientRelation();
   }

   // etc
}

With no autowiring instructions until now, everything worked fine.

But if I want to start the application now, I get:

The bean 'ingredientRelation', defined in class path resource
[tacos/model/ingredients/IngredientRelation.class], could not be registered. 
A bean with that name has already been defined in file
[/home/aloy/IdeaProjects/taco-cloud/build/classes/java/main/tacos/model/ingredients/IngredientRelation.class]
and overriding is disabled.

Action:

Consider renaming one of the beans or enabling overriding by setting
spring.main.allow-bean-definition-overriding=true

Clearly, the Spring Boot application finds the same class (and actually the same file) twice on its search path.

I don't like the idea of allowing "overriding", it seems like an arbitrary hack.

I would rather have Spring did not scan the same class twice in the first place.

How do I tell Spring Boot to behave?

P.S.

Overriding works though. After adding

 spring.main.allow-bean-definition-overriding=true

to file "resources/application.properties", Spring application startup succeeds.