iPad Pro photos yellow - how to improve?

Hi all,

Bit of an unusual one this.

When taking photos (for eBay) using my 2018 iPad Pro, the pictures come out dull / yellowish unless I stick another object next to the lens - then the pics come out great. A bit of a nuisance as the camera is obviously capable. Is there any way to avoid this?

I’ve attached some pics below to demonstrate. The first shows a fork (dull / yellowish). Next, I stick a red can of spray near the lens and the fork looks great (doesn’t need to be a can, could be a finger or any object).

Thanks in advance for any advice