Steps to reproduce:
When vertical scrolling with a Magic Mouse 2 (using "natural" orientation), slow scrolling works fine. However, fast scrolling causes the page to reload... or at the very least, reset. This does NOT happen with my Magic Trackpad 2.
Orion and macOS:
Orion 0.99.109-beta (WebKit 613.1.12), MacOS 11.6 on MacBook Pro M1