I do get a lot of these warnings in /sources/subs/Metadata.integrate.php Line 238:
230: $smd = array(
231: '@context' => 'https://schema.org',
232: '@type' => 'DiscussionForumPosting',
233: '@id' => $this->data['href'],
234: 'headline' => $this->getPageTitle(),
235: 'author' => array(
236: '@type' => 'Person',
237: 'name' => $this->data['member']['name'],
238: 'url' => $this->data['member']['href']
239: ),
I am using PHP 8.1