TOC showing up when H6 is present

Just making sure this is a bug before filing the issue on github.

Given the following post, the TOC shows up as part of .Content in Hugo 0.56.3. If I make it into an H5, the TOC disappears.

---
title: Title
author: Bruno Amaral
type: post
date: 2007-11-14T08:00:09+00:00
slug: 
categories:
tags:
---

Lorem ipsum dolor sit amet, consectetur adipisicing elit. Incidunt, aliquid architecto repellendus delectus fuga doloribus culpa voluptate magnam illo natus magni fugiat vero ipsa quasi quibusdam. Similique esse quibusdam, nulla?

###### TOC TEST 10-08-2019