Certain area in the Nether causes extreme lag or a game crash when entered

Steps to reproduce

1. Create a world with seed 1063292310985219505, creative mode, coordinates on, mob spawning off.

2. Make nether portal and go the the nether.

3. Teleport or fly to 76 79 102 (on top of the tall warped tree).

4. Stand there for an hour or more.

5. Drop some items.

6. Save & quit, and note the world save file size.

Expected results

The items you drop fall at normal speed. The world save file size is very small since the explored area is very small and no mobs have spawned.

Observed results

The items you drop fall slower than normal. The worlds save file size is massive compared to the small explored area.

Analysis

The lag and massive save file size are due to continuous redundant pendingTick creation and failure to clear these pendingTicks in chunks that generate with large amounts of flowing liquids.

The Realm started becoming laggy in a certain area of the Nether out of nowhere. It causes lag for everyone, even when they’re in the Overworld. Sometimes, it becomes unbearable — it removed 40 blocks I placed, and in the worst case, I was disconnected and lost 40 minutes of progress.

I don’t have any addons, just a few texture packs that don’t cause lag. I also don’t have any large builds or redstone in the Nether that could be causing this issue. It’s like there’s an invisible laggy border — once I cross a specific block, everything I try to do becomes impossible: eating, building, breaking blocks, or killing mobs. Sometimes the entire Realm freezes.

This issue wasn’t always there. We used to go into that area with zero lag or problems. Then, all of a sudden, it became a laggy zone — and I didn’t change or build a single thing there.