Glitch

I have been using this app for a long time now and its always been my favorite, but Im having a problem with it on the iPhone 7 plus. When you Launch the app, landscape mode cuts the screen in half, also when Im taking video at 4K 100mbs nothing ever saves to my camera roll, even when I have it set so it does. Instead it goes to the filmic library where when I try to save it to the camera roll it says "error cant save to camera roll." I absolutely need this app, I use it almost every day. Could you please take this into account? Thanks

Jacob bocaj about Filmic Pro－Video Camera, v5.5