MISS from Cloudfront after HIT from Cloudfront
This is similar to this issue: Why are two requests with different clients from the same computer cache misses on cloudfront?
Depending on whether you provide the "Accept-Encoding: gzip" header or not, CloudFront edge server caches the object separately. Since browsers provides this header by default, and your site is likely to be accessed majorly via browser, I will suggest changing your curl call to include this header.
I was facing the same problem, after making the change in my curl call, I started to get a Hit from the browser on my first try via browser (after making a curl call).
Another thing I noticed is that CloudFront requires the full requested object to be downloaded before it will be cached. If you try to download the file partially by specifying the byte range in the curl, the intended object does not get cached, only the downloaded part gets cached as a different object. Same goes for a curl that was terminated in between. The other options I tried were wget call with spider option, but that internally does a HEAD call only and thus does not get the content cached on the edge server.