Model events not firing after findFirst() but do fire after save()

I am attempting to create a function in a Base Model class that would allow me to register events that would fire afterFetch, beforeSave and afterSave so that I can convert unix timestamps to mysql timestamps in utc, and vice versa.

I want the code to go into the base model, but actually call the registration in the actual model, in case there are models that shouldn't operate this way.

I have for a base model.

<?php
use Phalcon\Db\Column;
use Phalcon\Events\Manager as EventsManager;

class ModelBase extends Phalcon\Mvc\Model {

    /**
     * this attaches listeners to the beforeSave, afterSave, and afterFetch events of
     * the given model to convert the dates/datetimes to/from unix timestamps and mysql dattimes in utc
     */
    public function register_utc_conversion() {
        $eventsManager = new EventsManager();
        // Attach an anonymous function as a listener for "model" events
        $eventsManager->attach('model', function ($event, $model) {
        if ($event->getType() == 'afterFetch' || $event->getType() == 'afterSave') {
                $fields = $model->getModelsMetaData()->getDataTypes($model);
                foreach ($fields as $field => $type) {
                    if (($type == Column::TYPE_DATE || $type == Column::TYPE_DATETIME) && $model->$field !== null) {
                        $model->$field = $model->getDI()->get('datehelper')->from_utc($model->$field);
                    }
                }
        } else if ($event->getType() == 'beforeSave') {
                $fields = $model->getModelsMetaData()->getDataTypes($model);
                foreach ($fields as $field => $type) {
                    if ($type == Column::TYPE_DATE && $model->$field !== null) {
                        $model->$field = $model->getDI()->get('datehelper')->ts_utc($model->$field, 'Y-m-d');
                    } else if ($type == Column::TYPE_DATETIME && $model->$field !== null) {
                        $model->$field = $model->getDI()->get('datehelper')->ts_utc($model->$field, 'Y-m-d H:i:s');
                    }
                }
        }
        return true;
        });
        $this->setEventsManager($eventsManager);
    }
}

and for an actual model: (Bellsell_Model extends ModelBase)

<?php
class Bellsell_Invoices extends Bellsell_Model {

    public $id;
    public $invoice_number;
    public $customers_id;
    public $notes;
    public $arrive_date;
    public $pickup_date;
    public $ordered_from;
    public $include_sales_tax;
    public $po_number;
    public $created;
    public $updated;
    public $invoiced;

    public function initialize() {
        parent::initialize();
        $this->setSource('invoices');
        $this->hasMany('id', 'Bellsell_Items', 'invoices_id');
        $this->belongsTo('customers_id', 'Bellsell_Customers', 'id');
        $this->register_utc_conversion();
    }
}

if I load the model using findFirst, the eventsmanager doesn't seem to fire any events, however if I then save the model, the events appear to be fired. Putting code in the afterFetch() function of the model appears to work, but that defeats what I am trying to accomplish by using EventsManager and being able to register it on a per model basis. What would be the difference in the afterFetch() function working vs the EventsMananger not working. Quite certain I am missing something obvious. Using 2.0.8.