I just had it with:
Search string: "</span><hr /><div>$_var"
Replace string: "</span><br /><div>$_var"
Of course, with backup disabled, and 20+ large files affected

I assume I'm not the only one working with texts containing "$", so I guess it's something in my code that triggers it.
Not a very specific bug report, I'll do some research and get back with more details when I have some time.