So, a long time ago I battled the guy near the move poser and he used Minimize two times. My move missed and then I sent out a Skarmory, and surprisingly Feint hit like four times in a row. Ultra Moon, not Showdown!.
It's just pure luck. Feint doesn't ignore evasion or anything like that, it breaks through Protect and Detect. Your game is not glitched (or hacked), it's just your awesome luck!
Hope I helped!