$this->is_active not reached

I’ve tried it and it didn’t show any message after registering.

Is this on a TML page or a widget/shortcode elsewhere?

A TML Page; /login/?pending=activation

I use the shortcode on both the register and login page.

[theme-my-login default_action="login" show_title="0"]

Try removing the && $wp_query->is_main_query() part of the snippet I posted.

I did… no luck, sorry….

I have this website somewhere on a (protected) web location with test data.
You’re welcome to rummage around on it, if you’re interested.

Sure. You can send info to jeff [at] jfarthing [dot] com.

So, the problem is actually because TML assumes 0 is the default instance, as it is supposed to be when the loop is properly utilized. Obviously, since that is not the case with Timber, this is not true. In your case, the default instance is 1. This may not be true if there is an instance that is loaded before your main instance, such as in the header, etc.

By any means, since your current main instance is 1, I just modified the tml_custom_instance_setter function I gave you to trick TML into thinking the requested instance was 1, if there is no instance requested. Seems to do the trick!

function tml_custom_instance_setter() {
    $tml = Theme_My_Login::get_object();
    if ( empty( $tml->request_instance ) ) {
        $tml->request_instance = 1;
    }
}
add_action( 'init', 'tml_custom_instance_setter' );