Passing duplicate headers from request

Hi, all.
I have a simple kong nginx config, mostly defaults, but a custom kong handler. And errors set to log to syslog.
I also have a custom plugin and file-log plugin enabled,

The problem is when I send a request with duplicate headers with the same valid values. The request doesn’t come to the custom plugin, I have logged to syslog just after call to super .
The request doesn’t show up in kong-log’s file path as well.

What however happens is it goes to the error_page directive and the ngx.status gets set to 400.
But since I have a custom error log handler. I logged the ngx.req.get_headers() and that shows something like
{ ["content-type"] = application/json,["user-agent"] = curl/7.54.0,["accept"] = */*,["authorization"] = { [1] = Bearer test_token,[2] = Bearer test_token} }

I am not sure what is happening? Is there anything I am missing?

Found out the solution. The solution is no solution.
Nginx has a uniqueness check on the Authorization header explictly.

Not sure if that’s http spec. Will have to check.

So another way would be to pass comma separated values. But. bleh