TOC depth limited by 2

I’ve tried make TOC for all h1-h6 headings, but it makes only two level TOC.
Firstly, I thought that there was mistake in html template, but when I printed raw TOC – there was two levels as well.

Here is screenshot:

Also, I searched through getzola site and github issues, but I didn’t found any mention of this behavior.
Maybe I’m missing something…

BTW, I’ve used latest version compiled from source.

that’s very odd, we do have tests covering up to 5 types of headers…