Reserved connections weird issue

Hi all,

I'm having strange problem with one of our PG servers.

We're running legacy application (written in .NET) on several servers, it
creates large number of connections to a PG cluster (9.3.10), running on
CentOS 6. Lately the app team changed the deployment strategy in a way,
that in peaks it generated almost twice as much connections as before.

Strange thing is, that the connections filled all the way up to
max_connections and started to block the new connections with:

FATAL: sorry, too many clients already

related non-default settings:

max_connections = 800
superuser_reserved_connections = 10

It surprised me, that it didn't kept the reserved connections for the
superuser, as the application user is not superuser (got the Create DB
though). So I couldn't connect to the server to find out, what is going on.
I have verified that no superuser connections were on the server running in
that time.

In the process list majority of processes was in "authentication" state and
they were not shown in the numbackends of the pg_stat_database view
(collectd have had connections already established, so metrics were
gathered)

Any idea what I got wrong?

Thanks
Petr