Emoji search does not return predictable matches

As you add letters to your query, the order in which emojis are displayed is inconsistent.

In the following case, note that as I type smi, smiley_cat shows up first, but when I type smil, smile then shows up first. This also happens if you try typing in thumbs_up. The result returned for thu is different than thum.

A different but related problem happens when trying to type in point_up. As each character is entered, the selected emoji changes, and point_up_2_tone_5 is ultimately what is matched when you get to point_up.