Some of the solutions from that forum thread:
RequestReadTimeout header=0 body=0
This disables the 408 responses if a request times out.- Change the ELB health check to a different port.
- Disable logging for the ELB IP addresses with:
SetEnvIf Remote_Addr "10\.0\.0\.5" exclude_from_log
CustomLog logs/access_log common env=!exclude_from_log