[erlang-questions] Using ssl (via ranch) {active, once} behaving like {active, twice}

[Roger Lipscombe]

In R16B03-1, using SSL (with ranch) I'm seeing {active, once} behave
as if it was {active, twice}.

The client sends a message in 3 packets; I `receive` one packet, I
call `recv`, which delivers the 3rd packet; process fails to parse the
message and crashes; the crash log reveals that the 2nd packet is in
the process message queue.

What, if anything, am I doing wrong?

Cheers,
Roger.