ThunderBird does not seem like to my obsession to ALT+FS

I normally have an habit of heightened use of ALT+FS (even in preference to CTRL+S) so that the changes are captured instead of catapulting it.  A few recent observation and response from Thunderbird to this habit are:

Not sure whether the save operation to the IMAP server was slow that my intervals between ALT+FS requests was overlapping?