Confirmed, and Meet the Parents is a textbook case of it.

When you walk through a portal the screen fades to black and that black overlay *is* the loading screen — the game only starts drawing once the destination's art is in. To make that instant, the game pre-warms every map connected to the one you're standing in. The problem: that pre-warm step only queues textures. It never fetches the two things a map like this actually needs first — the lazy object-set metadata, and the base64 art bundle the pixels live in. Meet the Parents draws from the WeddingGL set, which we serve locally as bundles (Back_WeddingGL.json is 1.1 MB and Obj_WeddingGL.json is 1.8 MB) because the CDN won't serve that art. With no bundle loaded, the pre-warm resolves zero frames and warms nothing at all, so arriving there means fetching ~3 MB and decoding a couple of hundred images while you stare at black. Every bundled map behaves this way — the wedding maps, the interiors, the event and regional maps.

The fix is to make the cascade do the same two awaits the real map load does (ensureObjSets + ensureArtBundles) before it queues the neighbour's textures. After that the bundle is already in memory when you step through and the map paints immediately.

On Mom and Dad specifically: that's one NPC, id 9201003, "Mom and Dad" — the map genuinely has a single life entry in v83, so nothing is missing there. Their sprite is fetched lazily after the map draws, which is why they arrive a moment late. The cascade fix shortens that too; warming NPC art per neighbour is a separate, smaller follow-up.

Confirmed and fixed. The black screen IS the loading screen — the game fades to black and doesn't draw again until the destination map's art is in. We do pre-warm the maps on the other side of each portal, but the pre-warm was only asking for textures, never for the map's object sets or its art bundles, and without those there is nothing to ask for. Meet the Parents draws from the wedding art set, which is about 2.9 MB served from local bundles, so every byte of it was fetched and decoded after you'd already climbed the ladder, with the screen black. Mom and Dad turning up late is the same cause — they can't be placed until the map's art has settled. The pre-warm now fetches the object sets and art bundles first, then queues the textures, so the map is ready before you walk into the portal. The same fix speeds up every interior and event map, not just this one.