$select.selected is not updated when a new value pushed to ng-model #560

long story short, i have some async calls to api to get the ng-model initialized/updated accordingly. However, it doesn't update view of a multiple select right after..
i "sometimes" get some throw: "Error: [ui.select:multiarr] Expected model value to be array but got '5'"
altho it shouldn't be the case since the ng-model doesn't get updated from user input at that time but i suspect some race conditions between ngmodel->view and view->ngmodel

here is a simple plunker forked from the example:
http://plnkr.co/edit/mhQW9aCjoAir1DzVMPUk?p=preview
just a timeout push to multipleDemo.colors, there you see the ngmodel gets updated but select input is not..
no problem for non-multiple selects..