org.hibernate.PersistentObjectException: detached entity passed to persist in many to many relation

Question

I have a ManyToMany relation between my Walletand Voucherclass.

public class Wallet {

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    
    // The total amount in the voucher
    private float amount = 0;
    
    //the list of voucher in the wallet
    @OneToMany(mappedBy = "wallet", cascade = CascadeType.ALL, orphanRemoval = true)
    private Set<UserVoucher> userVouchers = new HashSet<>();
    
    @OneToOne(mappedBy = "wallet")
    private AppUser appUser;
}

Voucher

public class Voucher {

    @Id 
    private String code;
    
    private Date generationDate;
    
    private Date endDate;
    
    private float amount;
    
    private float minForBuy; // minimun needed to use the voucher during transaction
    
    private int nb = 1; // for example, for a voucher of 2 euros, with nb = 4, the amount will be 2/4, so 0,5€
    
    //the list of voucher in the wallet
    @OneToMany(mappedBy = "voucher")
    Set<UserVoucher> userVouchers = new HashSet<>();

    /**
     * 
     * @param code
     * @param endDate
     * @param amount
     * @param nb
     */
    public Voucher(String code, Date endDate, float amount, float minForBuy, int nb) {
        super();
        this.code = code;
        this.generationDate = new Date();
        this.endDate = endDate;
        this.amount = amount;
        this.minForBuy = minForBuy;
        this.nb = nb;
    }       
    
}

And my join table uservoucher

public class UserVoucher {

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    
    private int voucherNb;
    
    private Date activateDate;
    
    private Date useDate;
    
    @ManyToOne
    @JoinColumn(name = "wallet_id")
    @MapsId("walletId")
    Wallet wallet;

    @ManyToOne
    @JoinColumn(name = "vouher_id")
    @MapsId("voucherId")
    Voucher voucher;

    /**
     * required param
     * @param id
     * @param voucherNb
     * @param activateDate
     */
    public UserVoucher(int voucherNb, Voucher voucher, Wallet wallet) {
        super();
        this.voucherNb = voucherNb;
        this.activateDate = new Date();
        this.voucher = voucher;
        this.wallet = wallet;
    }    
    
}

In my test, i created a voucher, a wallet, then i add the voucher in uservucher list:

public Wallet addVoucher(String voucherCode, Wallet wallet) {
    
    logger.info("Add voucher with code {}", voucherCode);
    
    // first we check if the voucher exist and still valid
    if(!voucherService.isVoucherExistAndValid(voucherCode)) {
        throw new GaraAppUserException("The voucher doesn't exist or is expired", HttpStatus.NOT_FOUND);
    }
    
    //We get the voucher
    Optional<Voucher> voucherOpt = voucherRepo.findById(voucherCode);
    List<UserVoucher> userVoucherList = new ArrayList<>();
    
    //If the voucher exist
    if(voucherOpt.isPresent()) {

        Voucher voucher = voucherOpt.get();
        //We create the user voucher
        float amount = 0;
        for(int i=1; i <= voucher.getNb(); i++) {
            UserVoucher userVoucher = new UserVoucher(i, voucher, wallet);
            userVoucherList.add(userVoucher);
            amount += voucher.getAmount();
        }
        
        // save the list in the list of user voucher
        if(!userVoucherList.isEmpty()) {
            this.userVoucherService.saveAll(userVoucherList);
        }
        
        logger.info("The old wallet amount is {} ", voucher.getAmount());
        float totalAmount = wallet.getAmount() + amount;
        wallet.setAmount(totalAmount);
        //The amount changed
        logger.info("The new wallet amount is {} ", totalAmount);
        wallet = this.walletRepo.save(wallet);
    }
    
    return wallet;
}

I don't know why during the saveAll i got the error:

org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: com.gara.mappuser.model.wallet.Wallet; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: com.gara.mappuser.model.wallet.Wallet

All solutions i tried doesn't work for me. I saw the same question with 21 answers but none work for me. I tried cascade merged by still same issue. How could i correct it please ?