Do you get no training or different training than you anticipated when changing your availability?
This might be caused by the fact that availability in the coming days is higher, so the training plan generator determines that it's better to skip today and then do training sessions the days after.
What these rules come down to:
- If a training session today would prevent a session tomorrow (too many consecutive days) and tomorrow has more time available, then skip today to train tomorrow.
- If there was a session yesterday and the next two days have more availability than today, skip today to train the next two days.
Note that in both these cases, yesterday (and possibly the days before) were used for training. I don't know what he tested exactly, but if he went out for a ride regardless of what the plan was saying, he will get the advice to skip today every time.