Its can be fixed, the exception code is clearly show the problem while loading a save file, and thats the part where you should fix it
Furthermore, we are applying monthly exclusive benefits so there is no way we would let your save files from previous patch gone.
The problem is, there are "areas" where the error exception is not applied to us (hard to check), it seems work fine to us, but when tested to other people, the error occur. Thats why i announce this.
If there is no complain, i can assume the save files from previous patch work fine.