Downloading iCloud Photos - safari download file type

I'm having trouble downloading bulk photos from iCloud to my MacBook. I am downloading groups by months and had no issue for the first few I did, moved into file I wanted them in and called 'iCloud Photos'. However now when I try all I'm getting is a 'safari download' file named 'iCloud Photos.zip.download' that I can't unzip or open (throws me back to safari).

Any ideas? I've been searching and am aware that bulk photos zip upon download (although no idea why the first few lots didn't...) but I can't even unzip these. What am I missing? (not super savvy with this stuff!)

Thank you!