The initial creation of a Planner creates a Group with the corresponding privacy setting (public, private). When I change the privacy setting in Planner later it does not update Groups. However, updating the Group privacy setting does update the Planner. Seems like a bug to me, any plans to fix? The roadmap page is currently down so unable to check there.
I'd submit it as a ticket, I just had another premier ticket submitted where the Language settings don't align either. Don't anticipate something like that to be on the roadmap. That is how it should work already.
Lots of little inconsistencies that others have pointed out as well, that really need to be ironed out.
Rapid rate of change + things not working the way they should can create lots of headaches.