Modifying passthrough rendering using a shader

I have a shader I've written that modifies the color/rendering style of whatever is behind geometry that has the shader applied to it. It works great, but if I view passthrough behind the shader, the passthrough renders as black wherever the shader is. What gives? Any idea how to fix this situation? This is fundamental to the entire project I'm working on for Quest Pro. This post gives some insight into what may be going on: https://communityforums.atmeta.com/t5/Talk-VR/Scan-QR-code-with-passthrough-camera/m-p/959717 but I still need to find a solution. It seems that there should be a way for a shader to modify passthrough without compromising the users video feed from a security/safety standpoint.