Shadow/Mark Appearing Bottom Bright Shot Black Magic Pocket

Hello All

First time posting here and I'm new to film making so I hope this is the right place to ask. I've recently bought a Black Magic Pocket Camera and I am loving it but I have found when shooting in bright situations after I use the IRIS button the camera adjusts but I get a black shadow or spot at the bottom centre of the frame.

I have included some photo's to illustrate this the spot seems to get darker in darker light and almost disappear in bright spots. If I decrease the aperture manually (so the f number drops) it goes away but if I increase it or use the IRIS button it returns. As I can make it disappear in lower light or manually I know it's not dirt or anything on the lens. The lens I have is: LUMIX G Vario 14-42mm f/3.5 Asph. / MEGA O.I.S. Lens H-FS014042. I am shooting in ProRes HQ, Video at 30fps.

Again I am sorry if this is all a stupid question or error I have tried to find an answer on my own but having no luck. It seems different from the "black sun spot" problem as it's localised to a spot at the centre of the bottom and not in the sun or light source itself also I have updated to the latest firmware and issue still persists.

Any help would be greatly appreciated and I'm sorry if I have posted this incorrectly or wasted anyone's time but I'm at a loss and starting to worry it might be a fault in the specific camera.

Thanks so much.
Mitch Harris

Could be a bit of dust in the lens on on the sensor, more likely the lens. Are you using a ND filter in the outside shots? They look overexposed, so,if them lens is stopping down to f16 or s Allen, small dirt specks in a lens will show up. Try using a different lens to check if it is the lens causing this.
Cheers