What were you doing:
Folding nested headers works well, but I think the following is an edge-case bug. Basically, if you have nested headers (e.g. two H3’s under an H2) without a blank line in between the H2 and the first H3, then if you fold the first H3 and then attempt to fold the top level (H2), not everything below it to the next H2 gets included in the fold.
The video below makes it much more clear.
I also noticed a bug in the nesting. I have an H3 followed by two H2’s. Each H2 has bulleted items under them. If I fold the H2’s then the H2 #2 unfolds the H2 #1 and moves the first H2 #1 bullet into the H2 #1 row. When I refold H2 #1 (without moving the bullet back down, I see “” in H2 #1. I resolved this issue by adding a blank row between H2 #1 and H2 #2. However, it means, that I had to remove the auto created bullet first in order to get the blank space/row.