After digging a little further this does not come from CBSubs but from the integration whith Acymailing.
Code:
File: /var/www/html/libraries/vendor/joomla/database/src/Mysqli/MysqliStatement.php
Line: 433
Message: Field 'subscription_date' doesn't have a default value #0 /var/www/html/libraries/vendor/joomla/database/src/Mysqli/MysqliStatement.php(433): mysqli_stmt->execute()
#1 /var/www/html/libraries/vendor/joomla/database/src/DatabaseDriver.php(675): Joomla\Database\Mysqli\MysqliStatement->execute()
#2 /var/www/html/libraries/vendor/joomla/database/src/Mysqli/MysqliDriver.php(776): Joomla\Database\DatabaseDriver->execute()
#3 /var/www/html/administrator/components/com_acym/libraries/joomla/database.php(91): Joomla\Database\Mysqli\MysqliDriver->insertObject()
#4 /var/www/html/administrator/components/com_acym/classes/user.php(593): acym_insertObject()
#5 /var/www/html/components/com_comprofiler/plugin/user/plug_acymailingcbintegration/acym.php(336): AcyMailing\Classes\UserClass->unsubscribe()
#6 /var/www/html/libraries/CBLib/CB/Legacy/cbPluginHandler.php(880): getAcymTab->saveEditTab()
#7 /var/www/html/libraries/CBLib/CB/Legacy/cbTabs.php(1492): cbPluginHandler->call()
#8 /var/www/html/libraries/CBLib/CB/Legacy/cbTabs.php(1299): cbTabs->_callTabPlugin()
#9 /var/www/html/libraries/CBLib/CB/Database/Table/UserTable.php(1080): cbTabs->savePluginTabs()
#10 /var/www/html/administrator/components/com_comprofiler/controller/controller.user.php(171): CB\Database\Table\UserTable->saveSafely()
#11 /var/www/html/administrator/components/com_comprofiler/admin.comprofiler.controller.php(286): CBController_user->saveUser()
#12 /var/www/html/administrator/components/com_comprofiler/comprofiler.php(14): require('...')
#13 /var/www/html/libraries/src/Dispatcher/LegacyComponentDispatcher.php(71): require_once('...')
#14 /var/www/html/libraries/src/Dispatcher/LegacyComponentDispatcher.php(73): Joomla\CMS\Dispatcher\LegacyComponentDispatcher::Joomla\CMS\Dispatcher\{closure}()
#15 /var/www/html/libraries/src/Component/ComponentHelper.php(355): Joomla\CMS\Dispatcher\LegacyComponentDispatcher->dispatch()
#16 /var/www/html/libraries/src/Application/AdministratorApplication.php(143): Joomla\CMS\Component\ComponentHelper::renderComponent()
#17 /var/www/html/libraries/src/Application/AdministratorApplication.php(186): Joomla\CMS\Application\AdministratorApplication->dispatch()
#18 /var/www/html/libraries/src/Application/CMSApplication.php(294): Joomla\CMS\Application\AdministratorApplication->doExecute()
#19 /var/www/html/administrator/includes/app.php(61): Joomla\CMS\Application\CMSApplication->execute()
#20 /var/www/html/administrator/index.php(32): require_once('...')
#21 {main}
I could not trace if it comes from your integration of from one of our autoaction code but I cannot see which one it could be