It doesn’t make sense that missing a workout in a running training program locks that workout.
I got sick in the middle of a training program. I didn’t run for a few days, but managed to get two of three workouts done in week 3 (this was Your First 5k). I figured I’d squeeze 4 runs into the final week, but no… That run was gone for good! I wasn’t ready for the first week 4 run, and felt like if I’d been able to do that missed workout it would have made all the difference… I still struggled through the remaining week, but it wasn’t a good experience.
I’ve done a few cycling plans, and the experience was far more positive.