A board result missing is in all likelihood because the next board number shows on screen a little too quick. Players see Board e.g. #8 (or #16 or #24) top right, and assume they've finished the match and leave the table. They do not wait till the server tells them that the match is over. It is high on our to-do list to make it more obvious.
Till then: Do not leave a match before the server tells you so and maybe keep notes of the boards you have played.
OnLine Server > Last board played - Your part in this Match is now over. At the end of the Match you may return to your home table for a chat.