Odd character "/" gets inserted when sender name has an apostrophe

[timplaysguitar]

Setting the sender name (the one that overrides "Wordpress" as the sender, if I include an apostrophe in there, eg I set that name to "Jim O'Connell" when I hit save this becomes "Jim O'Connell" and the random "" appears in the sender name.

[Varbaek]

I think this is actually the \ backslash character you are referring to, which will be inserted on strings that contain the apos / single quote for example to avoid syntax issues. To avoid this, the code should be using prepared statements instead of mysql_real_escape_string or addslashes.
https://www.php.net/manual/en/function.mysql-real-escape-string.php
https://www.php.net/manual/en/function.addslashes.php