So basically on Kdenlive 24.12.2 on Windows if you cut a clip while having the effects disabled and then enable them and add keyframes, the keyframes don’t show on the timeline. That’s a bug.
It’s easy to reproduce. Drop a clip on the timeline, add an effect, disable the effects, move forward,cut it, enable the effects, move forward, add keyframe, keyframe won’t appear on the timeline unless you disable and reenable the effect.
Looks like a bug. Please log a bug report in the official bug tracker.