After some time exploring and testing the files, I think I tracked down the source of the crash. It seems to come from the file "zone.28.33.zone", and the Emperor Statue (SID: 264-zone28.33-INGAME-S23) thinking that it is inside the Concrete Gate building (SID: 268-zone28.33-INGAME-S23). Despite the building having been placed outside.
If the data is altered to make the statue think it's not inside, or at least not inside the gate, it seems to load the save fine. Though the statue will still disappear on game load. There is a second statue that is working fine (SID: 262-zone28.33-INGAME-S23), which I used to identify the differing values between the two.
Those values being:
flags
is inside building
isInsideBuildingC
isInsideBuildingCS
isInsideBuildingI
isInsideBuildingS
isInsideBuildingTYPE
player furniture Y offset
And the bugged one lacking the following values:
townC
townCS
townI
townS
townTYPE
While I'm not clear on the importance of all of the above values, seems clear they're all associated to it being inside/outside of a building. And changing even just a couple to match the working statues makes the save load correctly.
Let me know if you need any more data or files, and I'll be happy to try and acquire them.