After the browser (Firefox) tab has been open for a few hours a message appears as per below. The time varies a bit it seems so not sure what is populating the array, but refreshing the page clears up the problem.
P.S. Maybe add a tag for browser? D.S.
An error occurred running the Unity content on this page. See your browser JavaScript console for more info. The error was:
TypeError: WebGL2RenderingContext.compressedTexSubImage2D: Argument 8 can't be an ArrayBuffer or an ArrayBufferView larger than 2 GB