To repro, get some type bubbles in the source code, open second-level inspector and turn on paint flashing.
<rdar://problem/19736050>
I don't see this anymore! I only see repaints if types change. I tested on a few pages with type profiling, including inspecting the inspector and test pages that changed types every couple seconds. I checked to make sure we are polling for type updates as well. So, yay! I did notice another issue which I will file separately.