This issue has been reported where the long-form free ride advice (XATA) does not appear to align with the Magic Buckets guidelines.
However, they are both correct. 
The goal for the day is a particular ratio of low/high/peak strain which can be achieved in numerous ways.
Indoors this is evident by the variety of suitable workouts that meet today’s recommended XSS, Duration, Focus, and Difficulty. Some workouts will be closer to target values than others and they may have very different power chart profiles. But they all target a similar goal.
XMB takes a more pragmatic approach that is especially conducive to riding outdoors.
Instead of trying to replicate an indoor workout’s rigid format in conflict with the route you’ve chosen, you can execute micro-intervals as terrain and traffic permit.
Depending on your execution XMB recalculates in real-time and nudges you along in the right direction to fill your buckets accordingly.
In your example, you could conceivable follow the “free ride” advice while filling the buckets (ignoring XMB interval guidelines) and achieve the goal for the day. Or you might decide to do a combination of both. I.e. fill the buckets in whatever manner that works best for you on the route you’ve chosen.
I’ve used this combo approach indoors on occasion where I have EBC running on my phone while monitoring XMB on my Garmin 830. I’ll start a selected HIT workout in AUTO mode on EBC, switch to Slope mode on the hardest portions, and make my best attempt to comply with interval targets. Then, if necessary, switch to XMB to fill any remaining buckets prior to cooldown where I’ll switch back to AUTO. I don’t care if the Low bucket gets overfilled.
This is essentially what you can do outdoors using a combination of longer intervals plus XMB guidelines to meet the goal for the day. Others have mentioned joining group rides with bucket targets in mind, hanging in with the group, but finishing up solo to top off any remaining buckets. YMMV