Mail sent from osTicket is encoded as 'quoted-printable' thus, it inserts CR LF Space characters to wrap lines at 75 characters. Most mail readers are fine with this.
There's a possibility that your mail server is adding an extra CR, which can happen on some older mail servers, or that your mail client is not parsing the message properly.
You can change the encoding type on line 175 of inc/class.email.php though, despite the occasional hiccup, quoted-printable is probably still the better option for text encoding.