Upgraded to v2.2.8 Patch 1 recently and getting 2 specific errors in admin panel.
Error: Call to a member function getIdentifier() on null src/XF/Mvc/Entity/Finder.php:1392
#0 src/XF/Mvc/Entity/Manager.php(214): XF\Mvc\Entity\Finder->fetch()
#1 src/XF/Repository/Node.php(146): XF\Mvc\Entity\Manager->findByIds('XF:Forum', Array, Array)
#2 src/XF/Repository/Node.php(20): XF\Repository\Node->loadNodeTypeDataForNodes(Object(XF\Mvc\Entity\ArrayCollection))
#3 src/addons/Andy/SimilarThreads/Repository/SimilarThreads.php(174): XF\Repository\Node->getNodeList()
#4 src/addons/Andy/SimilarThreads/XF/Pub/Controller/Thread.php(54): Andy\SimilarThreads\Repository\SimilarThreads->getSimilarThreads(13, 71685, 'who helped apos...')
#5 src/addons/XFMG/XF/Pub/Controller/Thread.php(11): Andy\SimilarThreads\XF\Pub\Controller\Thread->actionIndex(Object(XF\Mvc\ParameterBag))
#6 src/XF/Mvc/Dispatcher.php(352): XFMG\XF\Pub\Controller\Thread->actionIndex(Object(XF\Mvc\ParameterBag))
#7 src/XF/Mvc/Dispatcher.php(259): XF\Mvc\Dispatcher->dispatchClass('XF:Thread', 'Index', Object(XF\Mvc\RouteMatch), Object(XFMG\XF\Pub\Controller\Thread), NULL)
#8 src/XF/Mvc/Dispatcher.php(115): XF\Mvc\Dispatcher->dispatchFromMatch(Object(XF\Mvc\RouteMatch), Object(XFMG\XF\Pub\Controller\Thread), NULL)
#9 src/XF/Mvc/Dispatcher.php(57): XF\Mvc\Dispatcher->dispatchLoop(Object(XF\Mvc\RouteMatch))
#10 src/XF/App.php(2351): XF\Mvc\Dispatcher->run()
#11 src/XF.php(517): XF\App->run()
#12 index.php(20): XF::runApp('XF\\Pub\\App')
#13 {main}
ErrorException: [E_NOTICE] Undefined index: src/XF/Mvc/Entity/Manager.php:584
#0 src/XF/Mvc/Entity/Manager.php(584): XF::handlePhpError(8, '[E_NOTICE] Unde...', '/home/-----/p...', 584, Array)
#1 src/XF/Mvc/Entity/Finder.php(1391): XF\Mvc\Entity\Manager->hydrateFromGrouped(Array, Array)
#2 src/XF/Mvc/Entity/Manager.php(214): XF\Mvc\Entity\Finder->fetch()
#3 src/XF/Repository/Node.php(146): XF\Mvc\Entity\Manager->findByIds('XF:Forum', Array, Array)
#4 src/XF/Repository/Node.php(20): XF\Repository\Node->loadNodeTypeDataForNodes(Object(XF\Mvc\Entity\ArrayCollection))
#5 src/addons/Andy/SimilarThreads/Repository/SimilarThreads.php(174): XF\Repository\Node->getNodeList()
#6 src/addons/Andy/SimilarThreads/XF/Pub/Controller/Thread.php(54): Andy\SimilarThreads\Repository\SimilarThreads->getSimilarThreads(13, 71685, 'who helped apos...')
#7 src/addons/XFMG/XF/Pub/Controller/Thread.php(11): Andy\SimilarThreads\XF\Pub\Controller\Thread->actionIndex(Object(XF\Mvc\ParameterBag))
#8 src/XF/Mvc/Dispatcher.php(352): XFMG\XF\Pub\Controller\Thread->actionIndex(Object(XF\Mvc\ParameterBag))
#9 src/XF/Mvc/Dispatcher.php(259): XF\Mvc\Dispatcher->dispatchClass('XF:Thread', 'Index', Object(XF\Mvc\RouteMatch), Object(XFMG\XF\Pub\Controller\Thread), NULL)
#10 src/XF/Mvc/Dispatcher.php(115): XF\Mvc\Dispatcher->dispatchFromMatch(Object(XF\Mvc\RouteMatch), Object(XFMG\XF\Pub\Controller\Thread), NULL)
#11 src/XF/Mvc/Dispatcher.php(57): XF\Mvc\Dispatcher->dispatchLoop(Object(XF\Mvc\RouteMatch))
#12 src/XF/App.php(2351): XF\Mvc\Dispatcher->run()
#13 src/XF.php(517): XF\App->run()
#14 index.php(20): XF::runApp('XF\\Pub\\App')
#15 {main}