Test file sent via PM to dpJudas.
Steps to reproduce:
Just walk up to a door and press +use to open it. The doors are actually Actors with an animated model (2 frames). Using gl_ssao_debug 4, you can clearly see that the model normals are only correct for its initial frame - as the model animates, the normals aren't updated.
Note that the model only has 2 frames - opened and closed. Interpolation is taken advantage of here to make the door look like it's opening and closing smoothly. If you disable model interpolation (gl_interpolate_model_frames 0) you can see the true nature of the model animation. :) I am only mentioning this detail because if this ticket were to be fixed, the model normal recalculation would have to take interpolation into account.
Same in OpenGL and Vulkan.