Massive lag during Bullseye Landing challenge! Pls help!

A few days before I noticed that the new Bullseye Challenge starts to massive lag after the fourth or fifth landing attempt. Up until then I have had a steady high fps. The interesting thing is that if I exit the challenge to the main screen and start my own flight, the lag does NOT disappear. I have to close FS and restart it. I have never experienced this in any other circumstance, but I have experienced it every single time at Bullseye Landing! Has anyone else experienced this besides me?
Here is the short video that I recorded after closing Bullseye Landing and start another random flight: