Linux openSUSE 13.1 x64, KDE 4.13.2. Radeon HD 6870, FOSS video driver (Gallium / Mesa).
Worked: 2.6x. I don't know the precise version, but I remember this method worked an year ago.
Short description of error
In some Blender Internal animations, I use a noise texture in composite nodes to simulate static noise (the grain you get on real life cameras when filming in poor lighting conditions). To do this, I create a plane, create a material on the plane, create a texture on the material, and set the texture to type "noise". This generates a grainy texture, which (most importantly) is randomized each frame. I then put the plane on a layer I don't use (it's only there so I can easily select the texture if needed), go to composite nodes, add a an Input -> Texture node, select the grain texture on it, and link it to a Mix node accordingly.
I noticed that, since recent versions of Blender, the texture was no longer randomized each frame. After digging through the problem a bit, I noticed that procedural noise textures are now only randomized when Blender sees them as being used directly... and composite nodes no longer triggers this. For example, the noise texture is changed each frame if it's present on a surface visible in that frame, or set as a world texture. As a workaround, I set a light which is always visible to use this texture for color but with 0 influence, which tricks Blender into seeing it active and therefore randomizing it.
Please make Blender also randomize noise textures when they are used in composite nodes, even if no object seen by the camera has the texture.
Exact steps for others to reproduce the error
Described above. I also posted a small blend file which shows the problem; Open it up, press F12 to render, select another render layer once it's ready, then press F12 again to render a second time. The noise applied in composite nodes doesn't change between the two render attempts. However, if you add the texture to anything visible in the scene at render time, the texture will be renewed as expected.