So I'm just going to dump the errors here. Basically you got quite a few created, but others have had some with smaller collections and no known actual problems, but really I have no idea the impact of these. Still after reviewing them I dug into 3 of them more, 2 were on your custom page and the 3rd was more of anomaly and perhaps the root cause. I'll direct Alex to this thread and maybe he can have the dev take a look.
php 07/29/2016 - 20:13 User error: "total_decks_collected" is an invalid… flyers3003
php 07/29/2016 - 20:13 User error: "total_unique_decks" is an invalid render… flyers3003
php 07/29/2016 - 20:13 User error: "total_unique_images" is an invalid render… flyers3003
php 07/29/2016 - 20:13 User error: "recently_collected_decks" is an invalid… flyers3003
php 07/29/2016 - 20:13 User error: "newly_archived_decks" is an invalid render… flyers3003
php 07/29/2016 - 20:14 Warning: apc_store(): GC cache entry 'M34VdBeTDBssJ8XxE… flyers3003
php 07/29/2016 - 20:14 User error: "total_decks_collected" is an invalid… flyers3003
php 07/29/2016 - 20:14 User error: "total_unique_decks" is an invalid render… flyers3003
php 07/29/2016 - 20:14 User error: "total_unique_images" is an invalid render… flyers3003
php 07/29/2016 - 20:14 User error: "recently_collected_decks" is an invalid… flyers3003
php 07/29/2016 - 20:14 User error: "newly_archived_decks" is an invalid render… flyers3003
php 07/29/2016 - 20:20 User error: "total_decks_collected" is an invalid… flyers3003
php 07/29/2016 - 20:20 User error: "total_unique_decks" is an invalid render… flyers3003
php 07/29/2016 - 20:20 User error: "total_unique_images" is an invalid render… flyers3003
php 07/29/2016 - 20:20 User error: "recently_collected_decks" is an invalid… flyers3003
php 07/29/2016 - 20:20 User error: "newly_archived_decks" is an invalid render… flyers3003
php 07/29/2016 - 20:20 Notice: Undefined variable: cache in Drupal… flyers3003
php 07/29/2016 - 20:20 Notice: Undefined variable: data in Drupal\mycollection… flyers3003
php 07/29/2016 - 20:20 Notice: Undefined variable: cache in Drupal… flyers3003
php 07/29/2016 - 20:20 Notice: Undefined variable: data in Drupal\mycollection… flyers3003
Type php
Date Friday, July 29, 2016 - 20:20
User flyers3003
Location
http://www.portfolio52.com/collection/52/images/custom" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Referrer
http://www.portfolio52.com/collection/52/images" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Message <em class="placeholder">Notice</em>: Undefined variable: data in <em class="placeholder">Drupal\mycollection\Controller\ViewcollectionController->displayCollection()</em> (line <em class="placeholder">96</em> of <em class="placeholder">/var/www/html/releases/20151122194555/modules/mycollection/src/Controller/ViewcollectionController.php</em>).
Severity Notice
Type php
Date Friday, July 29, 2016 - 20:20
User flyers3003
Location
http://www.portfolio52.com/collection/52/images/custom" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Referrer
http://www.portfolio52.com/collection/52/images" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Message <em class="placeholder">Notice</em>: Undefined variable: cache in <em class="placeholder">Drupal\mycollection\Controller\ViewcollectionController->displayCollection()</em> (line <em class="placeholder">44</em> of <em class="placeholder">/var/www/html/releases/20151122194555/modules/mycollection/src/Controller/ViewcollectionController.php</em>).
Severity Notice
Type php
Date Friday, July 29, 2016 - 20:14
User flyers3003
Location
http://www.portfolio52.com/user/52" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Referrer
http://www.portfolio52.com/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Message <em class="placeholder">Warning</em>: apc_store(): GC cache entry 'M34VdBeTDBssJ8XxE_lmVzIFW6sPBbbqwUbtk3yUoeg::config::rdf.mapping.node.deck' was on gc-list for 3607 seconds in <em class="placeholder">Drupal\Core\Cache\ApcuBackend->set()</em> (line <em class="placeholder">188</em> of <em class="placeholder">/var/www/html/releases/20151122194555/core/lib/Drupal/Core/Cache/ApcuBackend.php</em>).
Severity Warning