Today's "DUH!  I'M AN IDIOT!" award goes to...me.  Yay, I won something.

 

I get it for not putting the /* on the end of the path I was trying to publish with ISA.  The /extranet.aspx links should now work.  The funny thing is I forgot it despite there being other paths published in the same rule that correctly had the /* at the end.  So, basically, if I had just like, looked at the screen maybe, I should have seen the problem immediately.