IMPOSSIBLE for the drone to fly with propellers on the wrong motors. The drone would immediately flip on power up of motors. By mismatch I assume you meant that you used 2 original props and 2 newer quieter props together? The flight controller could handle that easily I imagine.
I had built this rather large hex copter, took my time, super clean build. Went to power it up for a maiden flight....it immediately flipped, no matter what I did. I checked everything, re-checked again. I was sure I was super careful on everything. DOH! what happened when I programmed the flight controller was, I had turned the frame 180 degrees, so programmed the motors wrong in the programming. I was just glad that I didn't break anything when it kept flipping. Straightened out the programming and viola! Perfect flying machine.
In all my years of flying drones, I have never had any props fly off because they were not on tight enough, or I somehow didn't put them on correctly. ALWAYS take the extra 30 seconds for each prop and make sure they are on correctly and tight. You won't regret taking that small amount of extra time. The push-turn props make is so easy, but don't get complacent.