[2020] Any reason why the Dense Essence Blocks textures change?

While starting my rcing grind. I noticed the the dense essence and dark essence blocks texture changes throughout the day. Early in the morning/day the blocks have a smooth look, but in the afternoon the essence blocks change to their normal rough textured looked.

I thought it might have been Runelite going a little weird at first, but it is that way on mobile aswell.