Git send-email not sending email patches as subsequent replies

From: David Davis <davidjamesdavis.djd@gmail.com>
Date: Apr 6, 2018, 19:28 UTC
Message-ID: <CANqAOmsZxpbkT3YFcZTOeRx2gnxnzc+_C-amVQjKSE=0m7_n7w@mail.gmail.com>

Hello, I have the following git send-email command:

git send-email -5 --quiet --thread --no-chain-reply-to --compose --subject='Recent Base Prototype Changes Summary' --to=davisdavid@google.com --from=davisdavid@google.com

It's sending emails but as 5 individual emails and not as subsequent replies as suggested on https://git-scm.com/docs/git-send-email below:

So for example when --thread and --no-chain-reply-to are specified, the second and subsequent patches will be replies to the first one like in the illustration below where [PATCH v2 0/3] is in reply to [PATCH 0/2]:

[PATCH 0/2] Here is what I did...
  [PATCH 1/2] Clean up and tests
  [PATCH 2/2] Implementation
  [PATCH v2 0/3] Here is a reroll
    [PATCH v2 1/3] Clean up
    [PATCH v2 2/3] New tests
    [PATCH v2 3/3] Implementation

What am I missing?

Thanks, David