OpenImageDenoise 1.3 assumes that the albedo and normal passes might contain noise (for example from motion blur or depth of field). That means it can misidentify texture detail as noise and blur it out.
With 1.4 you can denoise the albedo and normal passes through prefiltering, and then denoise the final image assuming those passes are noise free. Of course prefiltering could also misidentify texture detail as noise, so you could still lose texture detail. But I guess they found the prefiltering to be better at this. We’ll have to see how well it works.
Potentially we can also use the variance of the albedo and normal to influence the prefiltering. In areas without motion blur and depth of field where we are confident there is no noise, we could disable or reduce the influence of prefiltering.