i am facing the same problem, where my comments are sent (while infact they are not) specialy when i use the vertual keyboard.

i found away around it, first you need to know that after you hit enter to send your comment you have to wait for two or three seconds then u should get the blue "like" option, if you see it then you comment is sent 100%

To solve the problem , just use ur vertual keyboard to write the msg as usual then slide ur physical keyboard and press " right arrow, left arrow , up arrow , or down arrow couple of times" tell you see you full comment resized, then and only then you can press enter to send the comment and garantee it succesfully has been sent

hope this helps u fb guys