Yeah, there are some tactics like that. In general, the line chosen is the fastest and/or most forcing line.
If there really isn't a difference, say two options like a mate in 2 and mate in 3 (though it doesn't have to be one move difference) , you can report them via a link on the tactic (on the website).
I recently did some tactics. When I delivered checkmate the computer said "incorrect". I later noticed that there was another way to deliver checkmate which was rated as "correct" by the computer. I know for a fact that my way was also checkmate and I even got some points for it. Has anyone seen this before?