I had the same issue so i switched to niagara and 4.23 now it can record particles and you can even scrub through them ,i still have 2 particle systems with cascade left in the scene but they work normaly with activate/deactivate keyframe ,what i would look out for is when you pause the animation of the sequence when you wanna hit record i would scrub to the begining so it resets all the keyframes etc before recording for consistency of activation