I'm late to return to the thread, but this was the exact scenario we hit. We had it behind a CDN as well as behind an L4 load balancer for some very high volume

I'm late to return to the thread, but this was the exact scenario we hit. We had it behind a CDN as well as behind an L4 load balancer for some very high volume internal consumers, and when it would just blast back RST packets, the consumers would freak out and break connection, returning errors on their end that weren't matched in our logs, unless we were lucky and got a 499 (now Maxim can talk about standards). As a general purpose reverse proxy for many clients on the Internet, I'm sure that's fine, but in our use case this made nginx unpredictable and no longer desirable.