Under your own profile you should be able to check your own posts - maybe you can see which post it is from there?
i attempted to look through all 34 pages of that o___o;; my eyes are burning (i cant see them all at once can i? then i could use the 'find' tool)
and either I'm not clicking the right thing, or your method isn't working - is it the first one under "additional options" called "return to this topic" - cause I tried to uncheck that for some posts just to test but its still updates.. (I tried the news forum one, about the update, since it was really active)
... I dont suppose I can go to suggestions and see if anyone wants an "unsubscribe from topic" button? >.> I mean if the ignore button was so simple, surely this cant be too hard?