Camera Aspect Issue UE 4.24.3

Hi all I have a weird issue with camera aspect ratios. I have my FP camera set to 1.7777 (16:9) and have ticked the Constrain Aspect Ratio for it. Looks perfect on the iMac where I’ve been developing but becomes horizontally squashed when I test on a MacBook Pro. Anyone come across this issue and figured out a fix? I’m developing and packaging for MacOS at the moment. Many thanks