Every single time you click into someone's post to leave a comment, you are rolling the dice.
If you hit a six, then you will - no two ways around it - lose your post, after you click send and see some message from the server about it being busy doing things besides recording your comment. Sure... you can do the "back arrow" and sometimes that saves your tingling, frustrated ass... but when it goes "back" to a blank post-a-comment screen... well you're seeing red man... and that's your six.
I mean... this is only an issue when you're typing your little fingers off in some long reply... not the "yes / no" stuff...
So the advice...
There is a three to six second delay at the best of times after you click send.
I use that time.
Every single time I click send on a comment, I immediately right click on the text area, pick "select all", right click a second time and pick "copy".