I was getting an unusual error when submitting code that was correct. I then reset the code and clicked save and submit and it passed.
I believe that you were probably on one of the introductory levels, where they just say: Hit Save and Submit when you are ready to code! Either that or you went to a past level by accident and hit Save and Submit.
That might happen once in a while. By writting code and submitting it you make changes to some variables and states so when you tried something wrong it sometimes even has impact on your next run. A common problem is to overwrite console.log like this:
console.log = ("test)" instead of console.log("test")
seems like a tiny mistake that is easy to fix but once you fixed it the code will tell you that console.log is not a function because now it has a value of "test". By refreshing the page you now reset the built-in stuff and the memory and thereby maybe get rid of the problem caused by an earlier run.