blocking page that uses dynamic urls

The login form defaults to whatever value get_permalink returns, so if the permalink of the page is https://www.mysite.com/mylisting/ then that’s where the form will post.

There are a couple of ways you could change that. First, you could filter the form. The redirect_to parameter is a hidden field that can be filtered with wpmem_login_hidden_fields. The HTML for the hidden fields are passed to the filter as a string.

The other possibility would be to enact a filter upon the login process with wpmem_login_redirect. This filter happens during the login process. For that to work, you would need some way of passing the value for your listings to the filter.