This lesson is what's causing the problem: https://www.codecademy.com/en/courses/learn-git/lessons/git-teamwork/exercises/git-merge-ii
In the lesson, you are given the instructions
Now we'll use the git merge command to integrate origin/master into your local master branch. The command:
git merge origin/master
will accomplish this for us.
Typing in the code
git merge origin/master to the bash shell results in it telling me
merge: origin/master - not something we can merge
A few seconds later, an error message pops up and says:
Did you merge origin/master into your local master branch?
The answer is no. No, I did not merge it in because YOU DIDN'T LET ME!
This is an annoying problem that I hope gets fixed soon.
Browser: Chrome 53.0.2785.87 (Official Build) beta (64-bit) on Chrome OS 53.0.2785.87 (Official Build) beta (64-bit). However, this problem seems to be happening to many other people too, so I don't think browser is relevant.
I am also sending out a bug report too.