Scratch has 30 frames per second, so each frame should spend 1/30 seconds on screen, right? But scratch uses an inaccurate timer. Weirdly, this happens in Turbowarp as well. You can fix this by turning on Turbowarp's Interpolation function, or switching your monitor to 30 Hz.
I heard about this and decided to make a project to test it. Part of start speech from Griffpatch (slightly adapted) Music is Bloodbath (Geometry Dash)