FieldHandlerInterface::getEntity() might return NULL.

modules/recurring_events_registration/src/Plugin/views/field/EventInstanceCapacity.php

@@ -67,6 +67,9 @@ class EventInstanceCapacity extends FieldPluginBase {
    */
   public function render(ResultRow $values) {
     $event = $this->getEntity($values);
+    if (!$event) {
+      return $this->t('N/A');
+    }
     $this->registrationCreationService->setEventInstance($event);
     $capacity = (int) $this->registrationCreationService->getEventSeries()->event_registration->capacity;
     if ($capacity === -1) {

modules/recurring_events_registration/src/Plugin/views/field/EventInstanceRegistrationAvailability.php

@@ -26,6 +26,9 @@ class EventInstanceRegistrationAvailability extends FieldPluginBase {
    */
   public function render(ResultRow $values) {
     $event = $this->getEntity($values);
+    if (!$event) {
+      return $this->t('N/A');
+    }
     $capacity = $event->get('availability_count')->getValue()[0]['value'] ?? 0;
 
     if ($capacity === -1) {

modules/recurring_events_registration/src/Plugin/views/field/EventInstanceRegistrationCount.php

@@ -26,6 +26,9 @@ class EventInstanceRegistrationCount extends FieldPluginBase {
    */
   public function render(ResultRow $values) {
     $eventinstance = $this->getEntity($values);
+    if (!$eventinstance) {
+      return $this->t('N/A');
+    }
     return $eventinstance->get('registration_count')->getValue()[0]['value'] ?? 0;
   }
 

modules/recurring_events_registration/src/Plugin/views/field/EventInstanceWaitlistCount.php

@@ -26,6 +26,9 @@ class EventInstanceWaitlistCount extends FieldPluginBase {
    */
   public function render(ResultRow $values) {
     $event = $this->getEntity($values);
+    if (!$event) {
+      return $this->t('N/A');
+    }
     return $event->get('waitlist_count')->getValue()[0]['value'] ?? 0;
   }