It seems that when you define a binding snippet of HTML using the data-template and nest a second data-template the parent template is incorrectly re-rendered when the child collection is changed.
I have created two JSFiddle projects that demonstrate the issue in 2012.2.710 and the the code working correctly in 2012.1.322.
The data set that I am working with in my project can contain 1 to many image sets (collections of images AKA a layer) and each image set can have 0 to many images.
When I attempt to add a new image to the image set's images array the MVVM bindings refresh for the image set and render a second time using the selected image record as a new "image set" resulting in the entire snippet being repeated on the page.
This behavior did not exist in 2012.1.322.
The expected behavior of the code I have provided is that when you click add image the new image will be appended to the images already displayed.
My sample project:
Using Kendo 2012.1.322 (working correctly)
Using Kendo 2012.2.710 (incorrectly rendering the parent data-template)