Looking at the code nothing seems obvious, but I don't think I've ever tested that deep into year 2, so there may be bugs that crop up from extended play. I'll look into it this week and see if I can figure out what broke.
Anything beyond the first 90 days may have bugs that I just won't see yet. As development continues and the rest of the year gets fleshed out, I'm sure this kind of stuff will happen less.
Also I try to build in save converters with each version to bring forward older save files, but I can't promise they will always work. This early in development I'm constantly adding new features and adjusting the flow of the game, and sometimes that means removing or adding parts that conflict with earlier versions.
