Fortnite Falls From High FPS and Locks into Lower FPS (PC)

Recently while playing Fortnite, the game will lock itself into a lower fps after playing x amount of games. It’s is not a lag spike or any kind of stutter, but an immediate and stable change in fps that lingers until I restart the game. Fortnite typically runs around 130fps, but when this occurs, it falls and hovers around 100fps consistently. It will do this at random after playing any amount of games. It will happen after 3, 5, or 7 games, doesn’t matter. The only fix is restarting the game itself.

PS: using software like hwmonitor and Afterburner, there are no signs of temp, power, or voltage issues. And when this occurs, it is never in the middle of a game but begins from the very start of a match.

Any tips or suggestions are appreciated.