Jump adds the BOM, (bite order mark ), because there is a character outside of the 7-bit ASCII range. That means you have a unicode character in one of your strings. One way to remove the bite order mark would be to load the file into a blob, remove the first three bytes with blobpeek, and then rewrite the file from the blob. Load/save textfile() is the function you need, look for the blob option.
Edit textile->textfile
Craige