This is a change introduced in Bike 1.2 “Collapsing a collapsed row will collapse containing row”. It’s a little weird, but many outliners seem to work this way.
My main issue was the third example, where it’s not possible (without shortcuts) to expand B. But now that I’m trying to repeat the issue, I can’t. I’ll spend more time trying to figure out what I did (or how I confused myself).
Without the third example, I have no complaint, though I do think that an icon change would make it less unexpected.