Following is the function written in a service.

public Mono<BrandRest> createBrand(CreateBrandRequest request) {
        record BrandCategoryRest(Brand brandRest, List<CategoryRest> categoryRests){}

        return Flux.fromIterable(request.categories())
                .flatMap(category -> categoryClient.findByName(category)
                        .next())
                .collectList()
                .flatMap(categoryRests -> {
                    var brand = new Brand();
                    brand.setBrandName(request.brandName());
                    brand.setStatus(true);
                    brand.setDescription(request.description());
                    brand.setImageUrl(request.imageUrl());
                    brand.setNoOfProducts(0L);
                    return brandRepository.save(brand)
                            .flatMap(b -> {
                                for (CategoryRest categoryRest: categoryRests) {
                                    var brandCategory = new BrandCategory(b.getBrandId(), categoryRest.categoryId());
                                    brandCategoryRepository.save(brandCategory);
                                }
                                return Mono.just(new BrandCategoryRest(b, categoryRests));
                            });
                })
                .map(brandCategoryRest -> BrandRest.of(brandCategoryRest.brandRest(), brandCategoryRest.categoryRests()));

    }

In this, the brandRepository.save(brand) is working fine and saving the entity in the database. But
brandCategoryRepository.save(brandCategory) is not saving any record in the database.

I am using postgresql as database.