It's the page from cloudflare. It shows whenever cloudflare is throttling on the front end. And other than the customizations to the look, putt has almost zero control over that page or when it shows up exactly.
It would sort of be like a real 404 page from the webserver that never made it to the app server, except its from the dispatcher on the front end of the cloud vendor.
The sticky seemed a bit weird, in the same way that some of his interactions often are with site users. You can get that cloudflare banner for other related reasons, and not actually always because you are "under attack".
I will chase one down next time I see it, if ever.
(post is archived)