emojis in contact names

I have a group of contacts that I want to call regularly that is always changing. I use a specific emoji in front of their name to signify that they are in that group (the group participants are always changing but the emoji stays the same). I used to be able to look them all up quickly by putting the emoji in the search bar at the top of contacts but as of a few weeks ago it's no longer working (no contacts come up). Is this because of a new software update? How do I get this function back?