Concatenate works all but one time

I have attached my wedding guest list. I have a column in which I have concatenated all of the email addresses ('X') and the appropriate semi-colons so I can quickly copy and paste the whole list. It seems to work 102 out of 103 times. I can't really explain any further because I am simply dumbfounded, I think I have been looking at it too long!

Any help would be greatly appreciated as this is driving me crazy!

PS, is there a more elegant or quicker way to accomplish this same task without macros or creating a new distribution list in outlook every time the list changes?