devtrackers.gg
I have been playing a Multiplayer game with one of my friends for some time. The game was started before GU15 with all DLCs enabled except Sunken Treasures and The Anarchist.
After GU15 we enabled Empires of The Sky in the game lobby before loading our game.
The DLC was added as intended and all content was playable perfectly fine (as expected).
While playing a few hours in we had a desync and had to recover the game. Afterwards the content of Empires of the Sky was technically still there (buildings, production chains, air ships) and could be copied (buildings) and placed. But there was no more access to the buildings in the building menu.
After saving and trying to reload the issue pertained.
Afterwards I had a look at different autosaves in the lobby.
All save games made BEFORE the Recover had the Empires of the Sky DLC activated, and everything is perfectly fine with them.
All save games made AFTER the Recover had the Empires of the Sky DLC set the deactivated and the situation described above is inherent to all of them.
The issue was fixed by reloading the last auto save before the recover.
Since then, the issue has not reoccurred even after desyncs and recovers.
My understanding is that the issue may occur when activating a new DLC on a save and a desync occurring, which leads to the usage of outdated information for the recovery (namely the list activated dlcs from before the save before the activation) (but that's just my personal guess).
If I remember correctly there was no "real save made between activating the dlc and the recovery operation, but no guarantee for that.
Best Regards.