Bizarre Chrome image caching issue

Hi,

This one has me completely stumped. Hopefully, some can help me figure this one out...

Do the following in CHROME (with Inspector closed)
1. Go to http://haskapa.staging.wpengine.com/
2. Scroll right down to the bottom of the page
3. You will see the 540x405 image for the latest post
4. Click on that image
5. You will then see the 1110x832 image at the top of the post
6. Click on the company logo to go back to the home page
7. Scroll to the bottom of the page
8. The latest post shows the 1110x832 instead of the 540x405 image

Why would Chrome cache this one specific image in this one specific location?

This does not happen in Firefox, Safari or IE/Edge. It also only happens in Chrome when the cache is on (I have Inspector set to turn off the cache when open. When following the steps above with Inspector open, the issue does not present itself). It also only happens on an image in this specific location, no other images are affected.

It's not a PHP/WordPress issue because I have tried added the img srcset as HTML to the page instead of using PHP/WordPress to generate that. Same thing happens. This seems to suggest that it is a Chrome caching issue.

This is also happening for multiple people on multiple computers and networks, both locally and remote.

Does anyone have any ideas. I've hit a wall.

Many thanks,
Mike