Let’s say you copy a big text (e.g. old notes, or code) into heading1 and it has some unexpected unescaped/block/code start characters, then it ruins the formating (+folding state) for everything after it.
This I a quite common problem if you paste a lot.
Parsing/formatting should restart after next/each heading.
Thus providing isolation barriers for runaway formaters.
(your wouldn’t want to format headings as code block anyway)
I have to manually check (scroll through) the whole doc to find where parsing failed.