Cron error "Object of class Feed could not be converted to string"

This doesn't sound like a problem with that view. If it's happening on a cron run, then it sounds like there are bad items in the queue. Those should have been deleted by the DB update, but maybe they didn't. See https://www.drupal.org/project/aggregator/issues/1067532 🐛 Deleted and edited aggregator feeds are restored from queue Fixed .

Run drush queue:delete aggregator_feeds and see if that fixes the problem.

Thank you @dcam that resolve the issue, there was a pending aggregator_feeds queue.

Automatically closed - issue fixed for 2 weeks with no activity.