3 replies

interaction with <a> elements caused failed prefetch cache requests, fixed by disabling speed brain

We’re experiencing an issue where interactions with <a> elements triggers prefetch cache requests to cloudflare that always return 503 errors, causing unintended redirects in webviews such as our custom app and the instagram in app browser on android devices. disabling the speed brain setting solved the issue. I wanna understand the cause of this issue, is it related to a cloudflare update or a settings change, or perahps it relates to a change in the website itself or its settings. Reverting all changes made after the issue began didn't solve it, only disabling speed brain worked.
Thanks!

AAmateur We’re experiencing an issue where interactions with <a> elements triggers prefet...

Chaika•5/5/25, 4:28 AM

Speed brain enables Speculation Rules https://developer.mozilla.org/en-US/docs/Web/API/Speculation_Rules_API with a speculation config which has the browser send a prefetch request on hover. Cloudflare then 503's those requests if the item isn't in cached, to prevent any issues with GET requests which modify state/only respond on cachable pages.
The curious thing is just the way your app is responding with it. It's hooked into every request and is being confused by the 503's or something?

AmateurOP•5/5/25, 12:22 PM

First of all thanks! The weird thing is that the problem occurred not only in our app, but all in app browsers (that are webviews).
My theory is that the 503 failing caused a race condition between events attached to the <a> elements, in a way that normal mobile browsers can handle but not webviews. This happened with ALL <a> elements in the site.
What I dont get is why this problem has suddenly appeared, was it because of speed brain activating? updating? or was it already activated but a change on my part, for instance in the headers or speculation rules caused the errors with the webviews?
Thanks again!

AmateurOP•5/8/25, 8:38 AM

Anyone? any insight will be much obliged!

interaction with <a> elements caused failed prefetch cache requests, fixed by disabling speed brain

Similar Threads

Similar Threads

Similar Threads