I started up JH just now with the Vulkan Renderer, and got weird speckles everywhere. This was a bit random...and now I realize I had a log I could have grabbed as well, but I opened the game up to double-check if this was a consistent thing before remembering that.
My specs:
nVidia GeForce GTX 970, driver version 26.21.14.3136
Intel Core i7-6700K