OK, it seems that I was a step behind. Sorry for the slow uptake. I thought it was a feature request to include sub-headers in autocompletion. I wasn’t aware that autocompletion already supported sub-headers.
So the bug report is about a special case of headings?
## Header plain text
### Sub-header
## Header with a [[wikilink]]
### Sub-header
Autocomplete works:
[[My note#header p…
[[My note#header plain text#…
[[My note#header with a …
Autocomplete does not work:
[[My note#header with a wikilink#…