I’ve noticed that the use of underscores causes problems with GMCode. If I have a post entitled “One, Two, Three", then you’ll have a permalink that ends with “One__Two__Three.” If you try then to refer to that in a subsequent post by permalink, you’ll end up with href="http://…/p123-One<span style="text-decoration:underline">Two</span>Three”

these are the *old* permalinks. New ones never have two subsequent _ .