Gulp / Browser Sync Error

We've got a web project using Gulp and Browser Sync, one of which is causing me heartache to no end. I can't build the development version with gulp and use browser sync, as every time I get an error right after the server is attempted startup. The message is:

throw new Error('Cannot set unknown key "' + k + '" on ' + recordName(this));

I haven't found any other solutions to this. The error is thrown from immutable.js, which Browser Sync apparently relies on.

I'm going crazy over this. Any solutions?