Image (product) thumbnails not displaying at consistent sizes

Thanks for providing such a versatile and adaptable theme and great support!

I was wondering if anyone would be able to shed any light on this issue:

I am using the Make theme to create a very simple online shop.

The product thumbnails generally display consistently as cropped squares, aligned in a grid, with one exception on this page:

https://donnareadtextiles.com/shop/product-category/scarves/

(the ‘kimonoblossom’ image towards the bottom of the page is cropped at a rectangular ratio, instead of square).

I was wondering if anyone would be able to explain what might be causing the display discrepancy here, and how I might be able to fix it?

Many thanks.