Shop product grid – missing products on last row

I seem to have an issue with the shop product grid missing products on the last row.

I’ve set my product page grid to 4x columns, 3x rows and a max of 12products (I have some 900 products). I’m using

However, I’m finding that the grid isn’t filling out with 12 products as I click through the product pages. Page1 will show 4x product on row 1 and 2, but only 1x product on row 3. Page 2 shows 4x products on row 1 and 2, but 3x products on row 3. I go to page 5 and it has 4x products on all rows.

I’ve tried changing the rows and columns to 3x and then back to 4x, updating to the latest version of the theme, reaching out to the theme developer, setting the theme back to the default theme, disabling all plugins, reducing the product thumbnail width and thumbnail cropping, clearing site cache, regenerating shop thumbnails. But not change.

Has anyone seen this type of grid issue before?

The page I need help with: [log in to see the link]