ConfirmRegister snippet neither activates user nor redirects them to the correct resource

[[!Register?
    &submitVar=`registerbtn`
    &usergroups=`3`
    &activationResourceId=`19`
    &activationEmailTpl=`lgnActivateEmailTpl`
    &activationEmailSubject=`Deine Anmeldung auf [[++site_name]]!`
    &submittedResourceId=`18`
    &validate=`nospam:blank,
  username:required:minLength=^6^,
  password:required:minLength=^6^,
  password_confirm:password_confirm=^password^,
  fullname:required,
  email:required:email`
    &placeholderPrefix=`reg.`
]]
 
<div class="register">
 
    <form class="form-signin" action="[[~[[*id]]]]" method="post">
        <h2 class="form-signin-heading">Registrieren</h2>
        <input type="hidden" name="nospam" value="[[!+reg.nospam]]" />
 
        <label for="username">[[%register.username? &namespace=`login` &topic=`register`]]
            <span class="error">[[!+reg.error.username]]</span>
        </label>
        <input type="text" name="username" id="username" value="[[!+reg.username]]" />
 
        <label for="password">[[%register.password]]
            <span class="error">[[!+reg.error.password]]</span>
        </label>
        <input type="password" name="password" id="password" value="[[!+reg.password]]" />
 
        <label for="password_confirm">[[%register.password_confirm]]
            <span class="error">[[!+reg.error.password_confirm]]</span>
        </label>
        <input type="password" name="password_confirm" id="password_confirm" value="[[!+reg.password_confirm]]" />
 
        <label for="fullname">[[%register.fullname]]
            <span class="error">[[!+reg.error.fullname]]</span>
        </label>
        <input type="text" name="fullname" id="fullname" value="[[!+reg.fullname]]" />
 
        <label for="email">[[%register.email]]
            <span class="error">[[!+reg.error.email]]</span>
        </label>
        <input type="text" name="email" id="email" value="[[!+reg.email]]" />
        <br class="clear" />
 
        <div class="form-buttons">
            <input class="btn btn-primary" type="submit" name="registerbtn" value="Anmelden" />
        </div>
    </form>
</div>

[[!ConfirmRegister? &redirectTo=`20`]]