Can't push to heroku. Updates were rejected because the remote contains work you dont have locally

Occassionally, I've been unable to push to heroku staging. I see this error: https://d.pr/i/SnFCC1 even though when I git pull it says it's up to date.

This was Gokul's response to my question about this: https://d.pr/i/4jMArO

Run this to force push to heroku staging:

git push --force staging master

Try to push normally to production. If you still can't, use this to force push to production:

git push --force production master