After some more testing, what I'm seeing is:
- load this saved game -> GC3 crashes
- in Steam, verify local file integrity -> 5 files have to be replaced
- after downloading them, re-verify local file integrity -> they are all good
- load this saved game -> GC3 crashes
- verify local file integrity -> 5 files have to be replaced
(and this is repeatable; can reaquire files to fix the problem, reload, crash, and need to reaquire again...)
Apparently the process of loading this saved game affects these 5 files every time....