No more adventure missions in space stage

It seems rather common that, at random, every new game in the space stage will stop giving me adventure missions. I'm not talking about getting the same 7 maxis missions over and over again, because I already subscribed to several sporecasts to get adventures with unlocked captains. I'm talking about not seeing the little diamond and flag over newly met empires' systems telling me that I can go there and ask for a mission and get an adventure.

No matter how many new empires I come across, I ask for missions and never get adventures anymore.

The first time I experienced this, was by editing my captain on the outside editor. But regardless of that, this has eventually happened on every game I've ever played, and I've been playing GA for 7 years now. I always though It was a problem with pirated files, but that's very clearly not the case anymore. For one save I also though that it was because I don't have bot parts installed anymore while the creature uses them, but my latest game has been entirely run on the steam copy I just bought, so I'm doubting that too.

To make matters worse, I actually did several things between getting my last adventure and my noticing the bug: I befriended my own empire from another save, then defriended it, then I visited the galactic core, and I shared the captain for that save on the Sporepedia.