grainey stuff on whites

[KBMS]

Just wondering if anyone has any suggestions as to what I am doing wrong in my settings.

I watched Home Alone last night and some scenes with whites in the distance like snow or clouds are "buzzing" with a grain like look and I noticed this in Rambo also, the whole movie was pristine except when they are on the river the white clouds in the distant sky are "buzzing"

I am assuming this isn't grain as it is color specific, but something else?