Filters on arrays only work once.

[jyasskin]

See http://jsbin.com/goqisemeta/5/edit. The filters work on the first binding, but because of how Polymer expressions handle arrays, subsequent updates to the arrays don't run through the filters again, meaning that the UI ignores any changes to array objects.

[addyosmani]

You're absolutely correct. Marking as a bug.

[albeec13]

Possible workaround is to make copies of arrays you modify, but that's clearly not the desired solution.

Ex: http://jsbin.com/fagipowore/2/edit