So, I picked up Oblivion (on the Xbox 360) again after a long hiatus, and, unsurprisingly, there was a new patch available which I downloaded as a matter of course. The problem is that the patch brought in quite a few bugs that I thought were long since squashed:

1. Occasional desynchronization of NPC speech audio and animations (multi-second delay before the animation starts).

2. More frequent freeze-ups during both gameplay and loading

The last four might be related because they seem to all happen consistently inside the Sigillum Sanguis:

3. Particle effects (from enchanted weapons) sometimes freeze in place after the an enemy dies (i.e. like fire-colored bubbles hanging above the corpses), or freeze in place to the player.

4. Sigil Stones (to destroy the Oblivion Gates and exit, not the ones in inventory) will not activate.

5. Game saves inside the Sigillum Sanguis are consistently corrupted and hang during loading.

Please fix, I'd actually like to play the game to completion.