indeed this is very odd, lots of O class availability on dates in Sept SVO-CDG , but neither DL, KE, AZ nor AF show any availability. However other SU destinations like GVA and FCO have seats available in O class and DL/KE/AZ/AF show availability, so the problem is only for some specific routes like CDG.

However it is not consistent for all partners for all days. For example, AZ showed no availability on the SVO-LAX route for any seats in business or eceonomy from mid-september until the end of the year, whereas DL showed just a few days with availability and AF shows significantly more days with both business and economy awards available. (I didnt check KE). So I doubt it is a general limitation from the side of Aeroflot but something more complex is going on...

Perhaps now Skyteam is using a system where partners provide cost of awards rather than simply a quantity of seats available, and each partner decides whether they are willing to offer them or not...