In everything in `EEVEE_renderpasses_postprocess` (or the corresponding renderpass_postprocess_frag.glsl) colors get divided by a 'currentSample'. This 'currentSample' is always incremented in `EEVEE_temporal_sampling_draw` (and also one more time before we reach `EEVEE_renderpasses_postprocess`. This results in a "off-by-one", slightly inacurate colors and slight inaccurate transparency (in certain passes like AOVs). Now decrement the currentSample `EEVEE_renderpasses_postprocess` again by one to compensate. Maniphest Tasks: T85261 Differential Revision: https://developer.blender.org/D10286