Steps to reproduce the issue

install joomla 5.2
install flexicontent
actived compatibility plugin
edit an item

An error has occurred.
0 Joomla\CMS\Editor\Button\Button::__construct(): Argument #3 ($options) must be of type array, string given, called in C:\wamp64\www\j5\libraries\src\Editor\Button\ButtonsRegistry.php on line 142

Call stack
--
# | Function | Location
1 | () | JROOT\libraries\src\Editor\Button\Button.php:51
2 | Joomla\CMS\Editor\Button\Button->__construct() | JROOT\libraries\src\Editor\Button\ButtonsRegistry.php:142
3 | Joomla\CMS\Editor\Button\ButtonsRegistry->initRegistry() | JROOT\libraries\src\Editor\AbstractEditorProvider.php:67
4 | Joomla\CMS\Editor\AbstractEditorProvider->getButtons() | JROOT\plugins\editors\tinymce\src\PluginTraits\XTDButtons.php:41
5 | Joomla\Plugin\Editors\TinyMCE\Provider\TinyMCEProvider->tinyButtons() | JROOT\plugins\editors\tinymce\src\PluginTraits\DisplayTrait.php:119
6 | Joomla\Plugin\Editors\TinyMCE\Provider\TinyMCEProvider->display() | JROOT\libraries\src\Editor\Editor.php:211
7 | Joomla\CMS\Editor\Editor->display() | JROOT\libraries\src\Form\Field\EditorField.php:251
8 | Joomla\CMS\Form\Field\EditorField->getInput() | JROOT\libraries\src\Form\FormField.php:474
9 | Joomla\CMS\Form\FormField->__get() | JROOT\libraries\src\Form\Field\TextareaField.php:94
10 | Joomla\CMS\Form\Field\TextareaField->__get() | JROOT\libraries\src\Form\Field\EditorField.php:138
11 | Joomla\CMS\Form\Field\EditorField->__get() | JROOT\libraries\src\Form\Form.php:458
12 | Joomla\CMS\Form\Form->getInput() | JROOT\administrator\components\com_flexicontent\views\category\tmpl\default.php:77
13 | include() | JROOT\libraries\src\MVC\View\HtmlView.php:415
14 | Joomla\CMS\MVC\View\HtmlView->loadTemplate() | JROOT\libraries\src\MVC\View\HtmlView.php:203
15 | Joomla\CMS\MVC\View\HtmlView->display() | JROOT\administrator\components\com_flexicontent\views\category\view.html.php:506
16 | FlexicontentViewCategory->display() | JROOT\libraries\src\MVC\Controller\BaseController.php:697
17 | Joomla\CMS\MVC\Controller\BaseController->display() | JROOT\administrator\components\com_flexicontent\controller.php:286
18 | FlexicontentController->display() | JROOT\libraries\src\MVC\Controller\BaseController.php:730
19 | Joomla\CMS\MVC\Controller\BaseController->execute() | JROOT\administrator\components\com_flexicontent\admin.flexicontent.php:264
20 | require_once() | JROOT\administrator\components\com_flexicontent\flexicontent.php:22
21 | require_once() | JROOT\libraries\src\Dispatcher\LegacyComponentDispatcher.php:71
22 | Joomla\CMS\Dispatcher\LegacyComponentDispatcher::Joomla\CMS\Dispatcher\{closure}() | JROOT\libraries\src\Dispatcher\LegacyComponentDispatcher.php:73
23 | Joomla\CMS\Dispatcher\LegacyComponentDispatcher->dispatch() | JROOT\libraries\src\Component\ComponentHelper.php:361
24 | Joomla\CMS\Component\ComponentHelper::renderComponent() | JROOT\libraries\src\Application\AdministratorApplication.php:150
25 | Joomla\CMS\Application\AdministratorApplication->dispatch() | JROOT\libraries\src\Application\AdministratorApplication.php:195
26 | Joomla\CMS\Application\AdministratorApplication->doExecute() | JROOT\libraries\src\Application\CMSApplication.php:306
27 | Joomla\CMS\Application\CMSApplication->execute() | JROOT\administrator\includes\app.php:58
28 | require_once() | JROOT\administrator\index.php:32