When I'm using webcam as a texture I get a lot of these warnings:
RENDER WARNING: texture bound to texture unit 0 is not renderable. It maybe non-power-of-2 and have incompatible texture filtering.
which happen until the webcam texture finally appears on the object. I think its trying to display the texture before the webcam feed has appeared.
Here's my webcam playground: https://www.babylonjs-playground.com/#1R77YT#10