The minimal pairs are actually designed to give you a lot of exposure to each minimal pair the first time you encounter it, and then an extra burst of exposure whenever you get one wrong. Sometimes it may seem "stuck" on a handful of words and go back and forth between the same two three or four times, but this is by design. If you find a pair really easy and just want it to go away, hit the 'Easy'/'Very Easy' button on the far right and you won't see it again that day.
Note: As of September 12th 2019, we no longer provide official support for our Anki based pronunciation trainers and word lists. You are more than welcome to still purchase and use them, but the support we are able to offer for these products is limited. For supported languages, these materials are already built into the Fluent Forever app.