Tulip Blobs

It is interesting how the colour in the tulips change as they fade to out of focus.  It’s not so much a colour shift, but the colours go blobby and blotchy.  I can’t remember film, especially E6, ever going like this, but this does look quite unnatural.  Click on the picture and check out the tulips at the very top. Even though this photo was shot with a nice camera and lens set up (Nikon D700 with Tamron 180 f3.5 Macro), I wonder if this is a fault that affects all digital cameras.  Or indeed, is it a fault?