WebGL - swiftshader - Unity 18.1, some scenes won't load

My team is working on a Unity WebGL application that is having issues running on lower end chromebooks.

The problem behavior is a scene fails to load and the user is presented with a black screen. Sometimes, a global scene with a simple quit interface loads, but the scene with actual content fails to load.

We can reproduce this specific case by turning off hardware acceleration in Chrome. At this point we are thinking the cause of the issue may have something to do with shaders, specifically Google's SwiftShader.

We have built the application with Unity 18.1, and we are wondering if an upgrade to the latest Unity version might help with this issue.