I’m meeting this problem also and it is very annoying when it happens. Some enterprise mail servers automatically add confidential note to every email sending outside, and that note is put outside the quote. It really becomes a chore to scroll through the length of all the thread per each email, just to get to the email’s text part.
Send a longer mail with several paragraphs divided by empty lines to someone.
Receive their response where they answer something for each of your original paragraphs.
Try replying to them by opening empty lines below their responses.
Only the first response will have correct quoting level (i.e. 2 indents for your original paragraph, 1 indent for their response, 0 indent for the text you are currently typing). Every other response you enter will have 0 indent for previous text in discussion.
Darn, quoting levels just don’t work! This is basic thing and messes up my discussions with colleagues.
This might be related to the issue I am having with inline replies. When I reply to the first email then the inline reply quoting works but as soon as I get a reply to that same email and try to reply to it then the inline reply doesn’t work as expected. What I mean by this is that nested inline replies don’t work at all. I have this issue both on Windows 10 and Ubuntu. I tried using Thunderbird and it doesn’t have this issue.