We have PROXY protocol support enabled on our ELB but we seem to be occasionally getting non-PROXY TCP connections to the EC2 instance behind the ELB. The instance's Security Group only allows incoming connections from the ELB.
Is it possible for ELB to initiate non-PROXY connections to the EC2 instance in certain circumstances when PROXY protocol support is enabled? When doing health checks, for example? This one really baffles us.