Many thanks. I have inspected my webpage, and found the anchor with its plain name. I appended it to the end of the url after #, but it didn't work.
Due to my limited server time, I've managed to find another Flexdashboard where the same issue is visible.
Whereas the tab link works well
https://matt-dray.github.io/earl18-crosstalk/04_leaflet-flexdash-dt-crosstalk.html#information
the h4 heading link doesn't work
https://matt-dray.github.io/earl18-crosstalk/04_leaflet-flexdash-dt-crosstalk.html#interactive-table
Considering the typical, no-scrolling layout of Flexdashboards, perhaps it makes sense if only columns and rows can be linked to. I'd be glad if there were a solution, although it is really a minor issue.