Hi aearle18, welcome to the Sony Forums.

Your "overlap" problem is quite unusual. If you can view the file on the camera display it's unlikely to be an issue with the way the camera captures the image. Certainly worth trying another card, as well as different download methods such as a card reader.

However there certainly seems to be an internal fault with the camera which I'd suggest is probably best left to a technician to repair. Check this link to a 'sticky' post to contact Sony Support in the UK. They should be able to help you evaluate the viability of a repair:

https://www.sony.co.uk/discussions/message/651957#651957

Best wishes

Mick