Like yourself, I have had several of my apps which were approved for sale then rejected once I submit a bug fix. Each app was totally original, they were games that I created from scratch including the artwork and processes yet they rejected each one but only after I submitted bug fixes.
I had one app that kept getting rejected for over 5 months - I did everything possible, I asked for clarifications, I asked that someone speak with me to help me understand, I even re-engineered a unique app with unique art work and processes to see if that would work and still they rejected it. When I appealed, it took months to be told that the original finding stands - nobody would speak with me.
Now I need to emphasize, I created the app from scratch, I did the artwork myself, I created every process not taking it from any other app anywhere and still it was rejected.
I'm not sure why Apple is doing this - maybe they're only allowing money makers onto the store - Apple after all only makes money when an app is sold or via IAP and all my apps make me money via Google ads, no IAP etc. So is that it?? They'll just keep smaller developers who don't make them money out of the app store?
Cheers.