Is a person considered a mocker if they play a video clip that covers the word "Qur'an" on a folder name containing a Mus'haf, and is it forbidden to play the video if the folder name does not contain the word "Qur'an"?

If the video operator did not intend it, then it is not considered mockery. One might play a video and not know or not remember that the device screen contains the word "Quran." Playing music videos (video clips) is forbidden.