Github branches never in sync even though they should be

I have two branches staging and master. They are in sync no differences.

Using github.com I follow these steps.

1. I create a new branch called Tim
2. make edits
3. commit edits to that branch Tim I just made
4. merge that Tim to the staging
5. merge staging into master

After step 5, I go to the staging branch and it says it's out of sync with the master branch, master branch is ahead by one commit.
I look to see what was changed and it was the staging merge.
If I sync master to staging, then master says it's behind one commit and the cycle never ends, they don't ever sync.

What am I doing wrong? I have a video showing this if it's helpful

"even though they should be" No, they shouldn't. That's not what "merge" means.

If you have this situation:

A -- B -- C <- master
 \
   --- X -- Y <- staging

Then if you merge staging into master, you have this:

A -- B -- C -- M <- master
 \            /
   --- X -- Y <- staging

As you can see, there is now a new commit M — the merge commit. And it is on master but not on staging. So master is ahead by 1. And that is exactly what you (should) expect.