How high are your Athlete Levels? If your ALs are high and your workout duration are short (less than 1:30), then this behavior makes sense because the AI would have fewer workouts of the right power and duration combinations to use to serve you the right workouts while your set FTP is lower. Then when your set FTP is higher your ALs are lower and it can pick from a much higher number of workouts with smaller differences between them.
So now it can find the Goldilocks workout for you each day rather than have to pick something too fatiguing or not stimulating enough. That’s my understanding.