Hey Jamie, my name is Sergey and I'm a developer for the Grammarly extension. Sorry to see you had so much trouble with Grammarly! That definitely wasn't our intention – quite the contrary.

Thanks to your debugging video pinpointing the issue, we have been able to fix it. There was a bug where Grammarly would try to poke nodes outside of the input field in certain cases. It should be fixed now in the latest version of Grammarly for Chrome – please check it out and let me know if it helped.