I have a custom static site generator at https://github.com/hrydgard/ppsspp-site. It breaks really badly with 6.3.1, while it worked perfectly in 6.3.0.

To reproduce, just clone the linked repo and type cargo run, then go to localhost:3000.

You'll see that the site headers are all a single repeated string instead of the correct strings - but not on all pages! This points to it being some hashing issue, which makes it likely related to #696 .