Bug with the Sales Zymphonies Theme 8.x-1.3

Hi,

My site gets
The website encountered an unexpected error. Please try again later.

I can see below error in the logs with this theme version & Drupal – 8.5.0version. Great if you can fix it.
I tried to apply this fix here https://www.drupal.org/project/sales_zymphonies_theme/issues/2841164 but I think its already applied.

Error: Call to undefined method stdClass::save() in sales_zymphonies_theme_form_system_theme_settings_alter() (line 300 of /homepages/33/d729076206/htdocs/Drupal8/themes/sales_zymphonies_theme/sales_zymphonies_theme.theme) #0 /homepages/33/d729076206/htdocs/Drupal8/core/modules/system/src/Form/ThemeSettingsForm.php(357): sales_zymphonies_theme_form_system_theme_settings_alter(Array, Object(Drupal\Core\Form\FormState)) #1 [internal function]: Drupal\system\Form\ThemeSettingsForm->buildForm(Array, Object(Drupal\Core\Form\FormState), 'sales_zymphonie...') #2 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/Form/FormBuilder.php(514): call_user_func_array(Array, Array) #3 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/Form/FormBuilder.php(271): Drupal\Core\Form\FormBuilder->retrieveForm('system_theme_se...', Object(Drupal\Core\Form\FormState)) #4 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/Controller/FormController.php(74): Drupal\Core\Form\FormBuilder->buildForm('system_theme_se...', Object(Drupal\Core\Form\FormState)) #5 [internal function]: Drupal\Core\Controller\FormController->getContentResult(Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\RouteMatch)) #6 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(123): call_user_func_array(Array, Array) #7 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/Render/Renderer.php(582): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #8 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(124): Drupal\Core\Render\Renderer->executeInRenderContext(Object(Drupal\Core\Render\RenderContext), Object(Closure)) #9 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/EventSubscriber/EarlyRenderingControllerWrapperSubscriber.php(97): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) #10 /homepages/33/d729076206/htdocs/Drupal8/vendor/symfony/http-kernel/HttpKernel.php(151): Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() #11 /homepages/33/d729076206/htdocs/Drupal8/vendor/symfony/http-kernel/HttpKernel.php(68): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1) #12 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #13 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #14 /homepages/33/d729076206/htdocs/Drupal8/core/modules/page_cache/src/StackMiddleware/PageCache.php(99): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #15 /homepages/33/d729076206/htdocs/Drupal8/core/modules/page_cache/src/StackMiddleware/PageCache.php(78): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true) #16 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #17 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(50): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #18 /homepages/33/d729076206/htdocs/Drupal8/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #19 /homepages/33/d729076206/htdocs/Drupal8/core/lib/Drupal/Core/DrupalKernel.php(657): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true) #20 /homepages/33/d729076206/htdocs/Drupal8/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request)) #21 {main}.

I have used your many themes including paid ones.

Many Thanks