Error visualizing tilt brush sketch in unity

Hi all! I write this in case this problem has happened to someone else and knows how to fix it. I have created a landscape in tilt brush to use it in a VR app. For this I have uploaded it to Poly.com and then I have downloaded Poly Toolkit in Unity. Once the landscape is downloaded and added to the hierarchy, it can only be seen through one of the lenses of my headset when pressing play. Through the other lens I see the default environment of Unity. It's weird because I've tried other materials downloaded from Poly and I can see them through both lenses: /
Does anyone have any idea what could be happening? The only thing that occurs to me is that the landscape has a lot of materials and produces that bug. I attach an image with the error.
Thanks in advance for your help!!