I’m finding this unreliable right now. Sometimes hitting e opens up the quick editor. Other times it opens up the full editor. This is even when I just highlight a single word with no special formatting, so I don’t think it’s falling back to the full editor by design.
I don’t know how consistently this will reproduce, but in the first paragraph of this post, “think” opens the full editor, “new” opens the quick editor, “spacing” opens the full editor, and “fine” opens the quick editor.
Also note that whatever I was doing got the draft for the post into a bad state. After a while, when I’d hit e a popup would appear telling me there was a draft open in another window (despite this being the only window) and I’d have to reload the page and delete the draft. This is despite me always just hitting ESC after the full editor appeared and never actually making any changes before closing it. At least in some cases, the very first time it opens the full editor instead of the quick editor, it saves a draft. I can immediately see it appear in the user menu where it adds the number of drafts in parentheses.
This also seems like a recent change, but I just noticed that after highlighting some text, the Quote button gets focused on. This means I can’t use Shift + Arrow to change what text is highlighted.
EDIT: Focusing on the Quote button (or something related) also messes things up on mobile (at least on iPhone). At first it doesn’t look like what you highlighted was actually highlighted. But this is just a minor UX issue. The bigger problem is that if you highlight something else without tapping the screen to unhighlight the first thing, the Quote button doesn’t move and hitting the Quote button quotes the first thing you highlighted, not what’s currently highlighted.