BuddyPress.org

wp_insert_post() takes an array as its first param. post_date is set to the current time by default so something is setting it to 0000-00-00 00:00:00.

If you’re talking about BuddyPress activity items (not WordPress posts) then recorded_time also defaults to the current time. Again, in this case there must be something in your plugin that is setting it to 0000-00-00 00:00:00.

Ref: https://codex.buddypress.org/developer/function-examples/bp_activity_add/