Loading "Mashup" packs creates 100% CPU load

After downloading the "Fallout Mashup Pack" attempted to load the "fallout 4 mashup" world.
See attached picture
Immediately Cpu usages spikes to 100% frame rate drops to 2fps. after roughly 2 minutes game crashes to desktop.

AMD ryzen 7 1800x 3.66GHZ
16GB pc2666
Asus GTX1060 Dual
ASrock taichi x370
Samsung 850EVO 250GB SSD

Title runs fine in all other game modes using Skins and textures @ ~7% cpu load