According to https://developers.facebook.com/docs/sharing/webmasters/images/ if image in post is smaller than 600x315 it still should be displayed as rectangular. But when I post picture 382x200 it get cropped to square. Where is docs information explaining this behaviour? How to prevent cropping?
I'm having this same issue. Were you able to get it resolved?
I use Wix for my website and spent a lot of hours setting up social share images for each product, and now they all get cropped.