NEVER DO DEPLOYMENTS BEFORE YOU WANT TO SLEEP
A simple statement that everyone understands. Nods. Agrees. Then ignores.
AWS ELB ERR_CONTENT_DECODING_FAILED
This was a real tricky one, and it took almost an hour of being in chat with AWS tech support to figure it out. The AWS ELB is extremely sensitive to malformed headers, so while chromium/firefox and others may willingly accept some malformation (such as multi-line headers), Amazon’s ELB most certainly will not.
Hope this helps someone, sometime.