My iPhone 8 Plus will no longer record 4K at 60fps and the slow mo is no longer 1080p at 240fps, why?

So literally this morning I was just in my settings having a look if there’s anything new and I decided to go into the camera setting again. Now when I purchased the phone I immediately went into the camera settings and change video resolution to 4K at 60fps and the slowmo to 1080p at 240fps. However this morning the options are no longer available and my only explanation is potentially low battery possibly? I’ve attached screen shots below. Has anyone else experienced this and if so what’s the reason for it changing? As this is one of the main reasons to why I purchased this particular model handset was purely for the camera quality.