What we see in the github UI is what's in the pull request, and the change isn't there. That's why I asked if you pushed the branch after you did the squash. Perhaps you pushed but didn't include --force? The push would be rejected without that since you (appropriately) squashed, but it's easy to not notice it was rejected. I've done that many times. :)

Yes, please remove the NOT_NULL_STRING_LENGTH_ONE_VALIDATOR since you'll need to update the branch anyway.