TYPO3 Core

After Updating from TYPO3 9.5.8 to 9.5.9 I get this error:

(1/1) Error

Cannot use object of type stdClass as array
in /_TYPO3-Sourcen/typo3_src-9.5.9/typo3/sysext/backend/Classes/Controller/BackendController.php line 254

        // Prepare the scaffolding, at this point extension may still add javascript and css
        $view = $this->getFluidTemplateObject($this->templatePath . 'Backend/Main.html');

        $collapseState = $this->getBackendUser()->uc['BackendComponents']['States']['typo3-module-menu']['collapsed'] ?? false;
        $view->assign('moduleMenuCollapsed', $collapseState === true || $collapseState === 'true');
        $view->assign('moduleMenu', $this->generateModuleMenu());
        $view->assign('topbar', $this->renderTopbar());

"Flush TYPO3 and PHP Cache" and "rm -r typo3temp" didn´t helped.
I see this error in 2/4 projects.
What could be the problem?