I see this issue under users:
Undefined constant "T4\Helper\T4PATH_BASE"
Call stack
Function Location
1 () JROOT/plugins/system/t4/src/t4/Helper/ExtraField.php:274
2 T4\Helper\ExtraField::onUserCompareForm() JROOT/plugins/system/t4/src/t4/Helper/ExtraField.php:109
3 T4\Helper\ExtraField::extendForm() JROOT/plugins/system/t4/src/t4/T4.php:174
4 T4\T4->contentPrepareForm() JROOT/plugins/system/t4/t4.php:149
5 PlgSystemT4->onContentPrepareForm() JROOT/libraries/src/Plugin/CMSPlugin.php:289
6 Joomla\CMS\Plugin\CMSPlugin->Joomla\CMS\Plugin{closure}() JROOT/libraries/vendor/joomla/event/src/Dispatcher.php:486
7 Joomla\Event\Dispatcher->dispatch() JROOT/libraries/src/Application/EventAware.php:111
8 Joomla\CMS\Application\WebApplication->triggerEvent() JROOT/libraries/src/MVC/Model/FormBehaviorTrait.php:169
9 Joomla\CMS\MVC\Model\FormModel->preprocessForm() JROOT/administrator/components/com_users/src/Model/UserModel.php:209
10 Joomla\Component\Users\Administrator\Model\UserModel->preprocessForm() JROOT/libraries/src/MVC/Model/FormBehaviorTrait.php:107
11 Joomla\CMS\MVC\Model\FormModel->loadForm() JROOT/administrator/components/com_users/src/Model/UserModel.php:126
12 Joomla\Component\Users\Administrator\Model\UserModel->getForm() JROOT/libraries/src/MVC/View/AbstractView.php:152
13 Joomla\CMS\MVC\View\AbstractView->get() JROOT/administrator/components/com_users/src/View/User/HtmlView.php:100
14 Joomla\Component\Users\Administrator\View\User\HtmlView->display() JROOT/libraries/src/MVC/Controller/BaseController.php:660
15 Joomla\CMS\MVC\Controller\BaseController->display() JROOT/administrator/components/com_users/src/Controller/DisplayController.php:130
16 Joomla\Component\Users\Administrator\Controller\DisplayController->display() JROOT/libraries/src/MVC/Controller/BaseController.php:693
17 Joomla\CMS\MVC\Controller\BaseController->execute() JROOT/libraries/src/Dispatcher/ComponentDispatcher.php:143
18 Joomla\CMS\Dispatcher\ComponentDispatcher->dispatch() JROOT/libraries/src/Component/ComponentHelper.php:361
19 Joomla\CMS\Component\ComponentHelper::renderComponent() JROOT/libraries/src/Application/AdministratorApplication.php:143
20 Joomla\CMS\Application\AdministratorApplication->dispatch() JROOT/libraries/src/Application/AdministratorApplication.php:186
21 Joomla\CMS\Application\AdministratorApplication->doExecute() JROOT/libraries/src/Application/CMSApplication.php:293
22 Joomla\CMS\Application\CMSApplication->execute() JROOT/administrator/includes/app.php:61
23 require_once() JROOT/administrator/index.php:32