Hello!

I opened highway blossoms a few minutes ago and got that achievement you get when you download the +18 patch, but I never downloaded it or did anything, just opened the vn as normal. I checked and the patch wasn't accidentally downloaded or something, it's not in my library!
Honestly, it's not a big problem, but I think it's good for someone to know about it, so it can be fixed in the future or in case someone else is going through the same situation! Have a good day!