Huge FPS drop while holding iron bars in PearlescentMoon's RTX Showcase Resource Pack (color, light and shadow RTX world)

While I was messing with the different block lightnings and combinations that ray tracing has to offer in the Color, light and shadow RTX world template, I found that holding iron bars in your hand makes the game's framerate drop to 5 fps. The framerate goes back to normal when you switch item. This only happens on this Resource pack as I restarted the game and went to the other worlds to check if this happens with other resource packs and it doesn't, then when i finished with those worlds I went back to the Color, Light and Shadow RTX world and equipped iron bars and happened again. I have attached a video of this problem and I hope this information helps to fix this bug.