The way airtable works with base titles is by default it will take the first few letters of your title and use this as the base icon if you haven't selected one of their native icons. In this case it will use the emoji instead if it is the first item in the title.
How to do this?
1. Go to the "Base Title"
2. Go to the beginning of the title
3. On Windows: Press Window Key + Full Stop (Win+.) to open the emoji menu.
On Mac: crtl+cmd+space
4. Type the first few letter of the emoji you want to find.
5. Click the emoji to add it to the front of the base title.