Happened to me as well with React Router + Hono - as the other comments mentioned, this will be a weird redirection caused by a Cloudflare redirecting HTTP to HTTPS requests.

This was caused due to my deploy environment running in a local network in HTTP. When requesting my own API on the application-level, my application would use HTTP, which then was redirected via 302 to the HTTPS protocol but lost its method (per specification) and defaults to GET. Forcing a HTTPS there fixed the problem.