The gang’s not all here for a “Stranger Things” event in New York City … because David Harbour and Millie Bobby Brown are noticeably absent.

Most of the cast was at the “Stranger Things: The Final Season Celebration” at New York City’s Paley Center Thursday … but David and Millie were nowhere to be found.

As we reported … David was initially supposed to attend the event, but he was scrubbed as an attendee on the event website.

David’s absence comes on the heels of some bizarre behavior in Encinitas, CA. He’s had a tough year, going through a messy divorce with Lily Allen.

Millie wasn’t scheduled to attend either, and she didn’t make a surprise appearance.

There’s been a rumored feud between David and Millie, but we’ve seen them together at other “Stranger Things” events recently.