Ended up figuring this out.

For posterity, there's a reg file online that contains zip settings: https://onedrive.live.com/prev?cid=9ac481c015daee85&id=9AC481C015DAEE85!52379&v=TextFileEditor
...

As stated in my post, these zips work fine in 7zip. However, that is a workaround and not a fix.

To take this a step further: the native zip utility works fine (Right click->Send to->Compressed...

I'm having this exact same issue. Not only do I get the "invalid file" error, but I also cannot simply double click on the zips to view them. This is an issue on ALL zips that are on my PC, including...