The idiomatic expression "to come as a surprise" means to happen unexpectedly or without warning. It can refer to an event, piece of information, or outcome that is not anticipated and takes people by surprise.
Everyone knows how he plays and it doesn't come as a surprise when we win by changing the register. (justarsenal.com)
There are people who have very exotic tastes and it should not come as a surprise when they decide to do something that is less than popular, as it were. (InterracialMatch.com)
It didn't come as a surprise as she had risen through the ranks of her current organization as high as she could and was looking for a new challenge. (connectthedotblog.com)