It was so obvious that every year they choose only finalist then why this year Imam was sent to choose the second one.
People who were saying that he would give it to Mandy were failed to see the bigger picture. Mandy is on top right now and does not need any ticket, Even Imam said to her yesterday that ap aur Prince do sab se tagde khiladi ho. BB knows it very well that she'll reach the finale on the basis of her huge fanbase and votes so they do not need to send Imam to give ticket to her. Imam was being nice to her because he likes her; she was being nice to him as an act of reciprocation. It has nothing to do with pass to finale.
Imam was sent especially for Priya. BB wants Priya as finalist as she is strong contestant that she proved in sand task but as she has the least number of fans/votes as compare to other HM so BB had to send Imam for her. And if you notice then he was targeting her in particular throughout the task that was the clear indication that she gonna win the ticket.
As for HM's votes are concerned then it was pretty clear by last weekend's ranking task that in HM's eyes he is below everyone and the reason was his inactive attitude generally in last two weeks and specifically in sand task.
Sand Task was game changing moment for many contestants.