I played through two routes and started another. I took a break for a bit and when I came back my game saves were there, but everything else, memorabilia, gallery images, side Bs I'd unlocked and access to completed chapters were all gone. If I used "skip read" it wouldn't skip over text I'd definitely completed. The story completion percentage on the opening menu also lists I only have done 1%.
I tried to go back into an old save to skip through to the end of the Limbo route because I had unlocked but not yet read his Side B, but it won't show up in the chapter selection, even though the end text said I unlocked it.
Does anyone know what this issue is or how to fix it? I don't understand why my saves are there but nothing else.

my progress went from 100% to a 0%. I think the update affected everyone's game. There hasn't been any fix so far...

same. went to 0% and I had finished 2 routes (i think). Wow. lol

I'm really bothered that I can't unlock the B sides any more.

Wait, this is my exact same problem! All my progress from my previous routes were gone? What update affected this?