Grid Layout option should not be available for videos
The current implementation of the grid layout was meant for the audio tab.
Therefore some issues have been noticed in the video tab where this option is available.
When entering in a media group containing one or more videos, the medias are invisible.
You can still select them and play them but they do not appear to the user.
I am using the version of the app that you can find on the master branch and the app is installed on an iPhone 8 Plus running with iOS 14.0