In hugo version 52 my table of contents would display headings 1-6. Version 60.1 is only displaying headings 2 and 3.
This is my env:
$ hugo env
Hugo Static Site Generator v0.60.1-96066756 windows/amd64 BuildDate: 2019-11-29T14:57:23Z
GOOS=“windows”
GOARCH=“amd64”
GOVERSION=“go1.13.4”