Changing texture on mesh works only with dynamic lighting


I have followed this tutorial to change a texture on a static mesh via a umg popup (Tutorial Unreal Engine 4 UMG Set Material. - YouTube)

Everything mostly works, but if i bake the lighting, every texture after the original one is just the grey chequered material. If i switch to movable lights/force no precomputed lighting, then it works fine.

The textures shouldn’t have any effect on the baked lighting, so not sure what the problem is.

Any pointers on getting it working? The baked lighting looks loads better, so would rather go that route than dynamic lighting.