503 Clickstorm\CsSeo\EventListener\ModifyPageLayoutContentEventListener::getResultsOfPage(): Return value must be of type array, false returned

[ingo-gm]

I'm using cs_seo 8.2.1 and getting this error for none admin user on our root page:

503
Oops, an error occurred!

Clickstorm\CsSeo\EventListener\ModifyPageLayoutContentEventListener::getResultsOfPage(): Return value must be of type array, false returned

Log also has this warning for that request
Core: Error handler (BE): PHP Warning: unserialize(): Error at offset 65533 of 65535 bytes in /example.com/vendor/clickstorm/cs_seo/Classes/EventListener/ModifyPageLayoutContentEventListener.php line 195

[ingo-gm]

Actually I get the same error with an admin user. The error depends on the view for the backend.

It does work in language comparision mode.