I started a new save and when I checked the farmhouses weren't changing with the season but everything else was fine. And I was able to manually change the farmhouse to match the season by clicking on it with the bucket to see that season's textures.
So I got a smapi log from a user saying season changes weren't working on buildings for Elle's seasonal buildings. https://smapi.io/log/477b19e129bb4801b635299811a40c3b
I started a new save and when I checked the farmhouses weren't changing with the season but everything else was fine. And I was able to manually change the farmhouse to match the season by clicking on it with the bucket to see that season's textures.