All I can find online of any substance is a site that states that they didn't show the final votes on TV. When they read them, they showed only 1 vote for Marty, then immediately 4 votes for Kelly B, leaving 1 vote unseen. Normally, they try to draw out the suspense as long as possible by showing all the "dissenting" votes, so a number of sites assume, like you have, that the final vote was 5-1 and one even goes so far as to claim that it was Sash that switched his vote (probably based on handwriting of the votes shown).
So, based on the fact that they didn't show a second vote for Marty and they usually would, there is reason to believe that someone may have switched. However, had everyone kept their original votes, the vote would have been 4-2, which could have also been the case since they never showed that last vote.
Unless they choose to discuss this in the final, we will probably never know for sure.