Originally Posted by Fyren
If you're sure you've set the table and column charsets, in your plugin you can try (SQL_)SetCharset if using 1.10 or maybe doing SET NAMES 'utf8mb4' if not to set the connection's charset.
Yes, this probably would solve the problem, but this option is not suitable because too many plugins use the database, and will have to rewrite everything.
It is easier to remove the symbol with a regular expression, but for some reason it does not work on SM.
I am interested to hear @asherkin