ELB allows unencrypted/http communication on port 443?

Question

I was testing a configuration of AWS ELB to use for SSL termination when I came across an intermittent issue...

Ocasionally, you can specify HTTP with port 443 (http://...:443) and ELB will pass the X-Forwarded-Proto as HTTPS (even though it is an unecrypted connection... ) ?

HTTP Port 80 -> Port 80

http://TestBalancer-513650940.us-east-1.elb.amazonaws.com
      HTTP_X_FORWARDED_PORT => 80
      HTTP_X_FORWARDED_PROTO => http

HTTPS Port 443 -> Port 443

https://TestBalancer-513650940.us-east-1.elb.amazonaws.com
      HTTP_X_FORWARDED_PORT => 443
      HTTP_X_FORWARDED_PROTO => https

HTTP Port 443 -> Port 443

http://TestBalancer-513650940.us-east-1.elb.amazonaws.com:443
      HTTP_X_FORWARDED_PORT => 443
      HTTP_X_FORWARDED_PROTO => https

Initially it didnt surprise me because I changed from htts://... to http://..:443 but then I fired up another system on a seperate connection and the http://...:443 worked on the first request - but then not subsequent requests...

Just wondering if anybody else has ever experianced this?