2013 Hyundai Sonata - Passed Engine Recall Test - Now Engine is Stalling

I have a 2013 Hyundai Sonata with about 88k miles on it. I took it in for the engine recall in December of 2017. They said it passed. I was a little worried because my mom has the same car, same year and hers failed and she needed the engine replaced. Today while driving the engine just stalled. No noise, and there were no lights on prior to it stalling. Luckily I was able to pull over. I turned the car off for about a minute and turned it back on and it started running again. I was almost home so I kept going and the same thing happened. Turned the car off and on and it started running again. I was able to get home and I drove up a few hills and around the block to see if it would happen again but it didn't. Sat in the car for a bit with it running to see what would happen but it seemed ok. But now I'm hesitant to drive it. Has anyone else had this problem? Should I take it back to the dealer and ask them to re-test it? I feel like they're going to blow me off since it already "passed." I originally bought the car used with about 12k miles on it and I believe the warranty with pre-owned cars runs out at 60k.