This patch mitigates an issue where saving (from Slot 4) could cause an issue when reopening, loading Save 4 then attempting to save again results in a crash. This is caused by the index becoming Nil due to a buffer overflow glitch.
Although this patch mitigates this issue by adding extra safety checks, we recommend in the meantime until a full solution is added that you save the game in Slots 1,2, and 3.