I know I’m almost three years late to the party, but I was running into the same issue and couldn’t find a solution.
I tried inserting an emoji directly in the database, which prompted an error. After researching that error, it seems the field’s collation type didn’t support all emoji (but some, like 3-byte ones would work). In my case, it was set to utf8_general_ci.
Solution: Change the field collation type to utf8mb4_general_ci to support longer-byte emoji.
To be on the safe side, make a backup of your database before operating this change. Hope this helps other people that run into this issue! 🙂
