Garmin Coach changing workouts throughout the day

I noticed the same but I think it is by design. Yesterday the watch told me mid afternoon that my recovery had been faster than expected (indeed it had been a sedative office day). In this case it still suggested no workout that day, but I can imagine that these suggestions will change if certain criteria are met. 
Training readiness is updated throughout the day and the assumption that is done in the morning may not be valid anymore in the evening, depending on your activities during the day. 
So, my guess would be that you had had a restful, easy day and recovered more than Garmin guessed you would.

I hope that someone more knowledgeable will be able to actually answer your question, but maybe this does help…

The new Garmin Coach plans are adaptive- so it is possible to experience this. I suggest reading through Garmin Run Coach for a thorough explanation on the training plans. I hope this helps!

Is there a way to make them less adaptive? I went to sleep thinking today was an interval day and drove somewhere to specifically do that now. Now that I am here with all the things required, all it is, is a base run day without any way of recalling the interval workout I was prepared to do mentally and physically. 

This would be really helpful. At the start of each training week, the plan seems to be well set out   I have woken up with training readiness high, sleep score high, but yet my long run that was scheduled yesterday is now a base run and half the time…

Makes me nervous in trusting Garmin Training for my first marathon - will i be prepared if the training is going to continue changing??

Is there a way where I can follow the plan and if my body isn’t up to it, rest or skip the suggested training?

Moreover. After AI changed the plan for Friday 3 times, finally a completed an aerob training. 2.5 horus with base cycling and 6x 1.5 minutes high watts.

Garmin coach took it for a rest day.

No comment for unprofessionality of this product as well.

Also when I do exactly the same what is the plan, other part of Garmin connect complains about different kind of shortage and gives advices against the plan.

It is absolute madness! I went to bed expecting a 5 hour long ride the next day, woke up and it was reduced to 4h 59mins, then once ready and prepared it had changed to a 3h 25min base ride. I rode 5 hours anyway and once I got back the workout had been deleted and replaced with a rest day. then later on in the evening it prompted me to go out for a 5 hour long ride again. A weekly adaptive solution would be perfect, I'm not a professional athlete so I need to plan my workouts around all my other commitments. It could recommend an alternative based on your health stats but should leave that decision to the user.

If you have Garmin watch or something track your daily activity and sync to Garmin connect then maybe possible.

But I admit this is madness.

15 warm up, 15 minutes cool down and between them 6x5 minutes: 20 seconds 600 watt + 5 minutes 160 watt.

So as per Garmin: 15+(6*5.3)+15=52 minutes :-)

yes, I also experienced this. After some recent updates, I haven't experienced changes in the training plan throughout the day anymore, but after each training the next training gets downgraded mostly to a regular base run. I always do the weekend long runs outside of the recommendation. There is still a lot of room for improvement for this feature. It feels like the training takes a pretty defense approach. 

I have been on the half marathon training plan for over two months now and from my experience:

- Daily base runs are much harder than Garmin expects them to be; the result is always VO2 or threshold. The plan isn’t learning from the results. Consequently they replace intervals and long runs with base runs later in the week to compensate. These base runs are harder than expected, compensate, not learning, repeat… 

- The plan seems to adopt nicely to poor rest, stress, bad sleep. In those cases it makes sense to downgrade the next workout.

- There is no way to change the plan due to injuries. I had to take it easy for a week and then build back up for another week. During that period, the plan was useless. Most people will experience small setbacks during a three or four month plan, so some flexibility would be nice here.