Sounds like nonsense to me.
I'm hoping they'll actually fix it.
No, it does makes sense: your GPU can run custom code - just like the bitcoin miners use. The timing for different sections can be measured down to the microsecond. If there are consistent timing differences for different sections in the GPU, it’s like a fingerprint.
And if that wasn’t enough, combine that with your CPU+GPU model information, your amount of installed RAM, any peripherals, language, general location and anything else that the browser will provide, it is probably enough to uniquely identify your computer amongst millions.