The channel blur plugin produces NaNs in 32 bit mode, especially when "repeat edge pixels" is on. The NaNs are on random frames every time the composition is rendered. This happens on both Windows and Macs, with the latest public release.
While the NaNs can be hard to see as individual pixels, they cause major problems when other effects are rendered on top.
I have attached an example project that reproduces this, and includes some rendered examples as well.