I have checked all of our sites which are up to date with WP and your plugin and they all have the issue. Sorry to be the bearer of that news.
After installing developer tools and running as an iPad (user agent only) the following information was revealed. I only have windows machines and to run the device as itself via my machine requires Safari 6 which you cannot get on Windows.
So as a summary, the main add media button on the generic page allows access to the media window to take or pick a picture. The single acf image field also allows access to the media window. Only when trying to use the image field in the repeater its doesn’t trigger.
Sorry I cannot debug any further… Very frustrating.
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