BuddyPress.org

I believe our issues are different but both may be directly related to conflicts between buddypress and feedwordpress. Buddypress is a sitewide plugin and the buddypress bar loads for every blog page – so every blog error could potentially be related to buddypress. I don’t have my problem when buddypress in deactivated. So my issue (and yours) with feedwordpress may be a buddypress issue rather than a wpmu issue.

Given your pm reply, I assume you’re not experiencing the same error as I. I have not seen the issue you reported either.

https://buddypress.org/forums/topic/feedwordpress-and-php-warning