Xbox Edition (PC Game Pass) Sim speed drops to 0.0 with runaway simulation thread (empty + old wor

On the Xbox Edition of Space Engineers running on PC (Game Pass), I am experiencing catastrophic simulation drops in all worlds, including Empty World in Offline mode with no asteroids, no planets, and no grids.

After ~10–20 minutes of play, the simulation speed begins to stutter, eventually repeating every 2–3 seconds. At its worst, sim speed drops to 0.00–0.03 and the game is effectively frozen.

This happens in:

• Brand new worlds (including Empty World).
• Old worlds that previously ran fine.
• Both Creative and Survival.
• Offline mode (no server activity).

Debug overlay shows:

• Sim speed: 0.03 (sometimes briefly 0.0).
• OPS: 2.
• Thread CPU Load: ~9074%.
• Simulation CPU Load: ~4773%.
• Server thread CPU Load: ~9074%.
• Server simulation CPU Load: ~4773%.
• Render GPU Load: normal.

The issue persists after:

• Reinstalling the game.
• Resetting configs/caches.
• Disabling autosave.
• Starting in Empty World with no asteroids.
• Running in Offline mode.

Steps to Reproduce:

1. Launch Space Engineers Xbox Edition (PC Game Pass).
2. Start an Empty World in Offline mode.
3. Play for ~10–20 minutes.
4. Observe simulation speed dropping in cycles, eventually tanking to 0.0 with CPU thread load spikes >9000%.

Expected Result:

Simulation speed should remain near 1.0 in an Empty World with no voxels or grids.

Actual Result:

Simulation collapses every 2–3 seconds, sim speed tanks to near 0.0, and the world becomes unplayable.

Platform:

• Xbox Edition (PC Game Pass)
• Offline mode