.set doesnt work with computed bindings, computed properties, or observers

[GrahenKraken]

I have an element which uses a <dom-repeat> template to make a list of <feed-post> custom elements, passing the item object as a custom model property. (<feed-post model=[[item]]>)

<feed-post> sends out an event, I catch it in another element (which is outside of all of this), and I use the event.model.set() approach to modify a single <feed-post>.

The problem is, the property that I am modifying changes only if it is directly bound to the dom (<span>[[model.x]]</span>). If I have it bound like icon="_icon(model.x,model.y)", the _icon method gets called, but uses the old values instead of the .set() ones.