Is there any plan to add more request code options to the Forwarding URL Page Rule?
Specifically, using a 307 or 308 code to redirect a non-HTTPS POST to the HTTPS URI should mean any form data that’s included in the request won’t be lost.
Currently only 301 and 302 are available in the Page Rules. And 301 is used for “Always use HTTPS” (Crypto setting) redirect.
Copied from here since it was apparently not important enough to acknowledge the first time: 307/8 Redirect on Page Rules