Hi!
I'm playing on Windows 10, singleplayer, English language, latest version of the game.
Summer 6 was a new 'green rain' day, everything was working just fine. I got to experience the new content, went to bed. The next day (Summer 7) was a normal sunny day, but I had to go do some irl stuff and since I hasn't done much that day I left the game (I exited the game properly through the menu). A few hours later I launch the game, load my savefile and it's the green rain again (on Summer 7) despite wiki saying it should only happen once per summer (I also already started the Summer 7 day before and it was sunny that time), but it seems not all aspects of it are there. I did a little bit of exploring and there are no weeds or unique trees that you should have on an actual 'green rain' day, my dog is outside running around as if it was a regular sunny day, the TV doesn't work however and the saloon is already open at the earliest time you can get there (like 6:30 AM in my case). There are probably a lot more things broken that I just haven't noticed.
I don't know if this is relevant but I'm also playing with the legacy randomization option enabled.