Oh my, yeah that sounds really annoying - you're focusing in one space in another app and suddenly swoosh you get pulled into a different one at random?No, I don't have Hush. Not really sure why there aren't more reports of this.
I have a particular Space (desktop) for Safari and I tend to do nothing else in that desktop, so when it grabs focus the desktop changes, which is quite obvious. Many users probably don't use multiple desktops, but I would imagine that Safari can also grab focus within a single one.