I've had the same issue

What I end Up doing is Creating a Filter for the XML Data that get's written
which will remove character 30's (the real character value of what you see
below) with a dash '-' - sometimes the bad character looks like a period in
notepad, and sometimes in html it looks like the box character above.

I'm keeping my eye on this - as it breaks the xmlp - and I'm also noting
to save the file using the cht stated above.