dirty reads of associations in hibernate second level cache

When enabling ehCache (2.7.0) as Hibernate (4.3.7) Second level cache, Hibernate returns the old collection association.

Model: A Member has a Wallet with Wallet transactions.

Scenario: a Wallet transaction is added to a Member in a transaction (with ehcache enabled). However, after the scenario (after the commit), the Wallet transaction isn't present in the Member, whereas it's present in the db.

Scenarios testing Code:

startTransaction(); // used to create a transaction through Spring.
member = findMemberById(); // Hibernate "get()" to retrieve member from Db.
final WalletTransaction walTx = member.getEnsureWallet().addWalletTransaction(10); // add wallet tx of 10 euro.
member.saveOrUpdate(); // will update the member and the wallet transactions through cascading
commitTransaction();

// assert wallet transaction is present
startTransaction();
final Taxer mem = findMemberById(member.getId()); // refresh member in session through it's PK, logging indicates it comes from cache.
// final Taxer mem = findMemberByLoginName(member.getLoginName()); // when retrieving the member through it's loginName, the test works.
assertTrue(mem.containsWalletTransaction(walTx)); // FAILS
commitTransaction();

The hibernate model member snippet:

<class name="com.core.domain.MemberDefault" table="mem" discriminator-value="Mem" >
   <component name="wallet" class="com.core.domain.Wallet">
        <set name="transactions" table="wallet_tx" cascade="save-update, delete" >
            <!--cache usage="read-write" /-->
            <key column="idMember" not-null="true" />

            <composite-element class="com.core.domain.WalletTransactionDefault">
              <property name="amount" type="big_decimal" column="amount" />
               .... (more props)
            </composite-element>
        </set>
  </component>
</class

The MemberDefault and WalletDefault class snippets:

public class MemberDefault implements Member {
  private Wallet wallet;
....
}

public class WalletDefault implements Wallet {
 private Set<WalletTransaction> transactions;

public void setTransactions(Set<WalletTransaction> transactions) {
  this.transactions = transaction;
 }

 public Set<WalletTransaction> getTransactions() {
  return this.transactions;
 }
}

Notes:

1. In case I not add the wallet transaction in a transaction (remove the first start/commit), the test is performed with success (The above is isolated testing code to reproduce bug).
2. In case I turn off the second-level, the test works.
3. In case I not retrieve the member from the Db through it's PK, but through it's loginName, such that a query is used by Hibernate, and as such the query cache, the test works.

I debugged, enabled hibernate/ehcache debug logging, modified the cache settings in hibernate, tried older Hibernate 4 and ehCache version, but don't seem to solve it, a bit frustrating.

Please some advice on how to solve this?