XF 2.3 Import style from beta 6 gets error.

[Mr Lucky]

Ignore this if it is not expected to be able to import a style from the previous beta, but I get this error when imported a style into beta 7 (style was exported from beta 6)

TypeError: XF\Service\Style\Import::setPropertyValue(): Argument #2 ($value) must be of type string, array given, called in /home/test/public_html/src/XF/Service/Style/Import.php on line 384 in src/XF/Service/Style/Import.php at line 443
XF\Service\Style\Import->setPropertyValue() in src/XF/Service/Style/Import.php at line 384
XF\Service\Style\Import->importProperties() in src/XF/Service/Style/Import.php at line 165
XF\Service\Style\Import->importFromXml() in src/XF/Admin/Controller/Style.php at line 489
XF\Admin\Controller\Style->actionImport() in src/XF/Mvc/Dispatcher.php at line 352
XF\Mvc\Dispatcher->dispatchClass() in src/XF/Mvc/Dispatcher.php at line 258
XF\Mvc\Dispatcher->dispatchFromMatch() in src/XF/Mvc/Dispatcher.php at line 115
XF\Mvc\Dispatcher->dispatchLoop() in src/XF/Mvc/Dispatcher.php at line 57
XF\Mvc\Dispatcher->run() in src/XF/App.php at line 2604
XF\App->run() in src/XF.php at line 533
XF::runApp() in admin.php at line 13