AI doesn't seem to be spending credits. They all have larger and larger amounts credits and I'm not sure I've ever seen the amount go down except when I sell them something.
When trading a resource the AI has too much of and doesn't want anymore, they will continue to decline the trade, even after taking off the resource they don't want.
When automating multiple surveys, they like to keep going after the same anomaly, and will tend to make trains. This is probably not a bug, but it'd be nice if they were kinda smart about it.
Minor races refuse to talk to you at all times - I imagine that's just because of the early build. Though they don't look to have a shipyard, so it's possible I just can't 'contact' them because I need to 'see' a ship/station to start communications.
Trading other races for Survey, Constructors, and Colony ships do not cost any administrators. Possibly also not a bug since it's a 'resource' you spend to build the thing, but it seems the AI undervalues their admins if it's not a bug.
'Promoting' an administrator citizen to a Minister says it gives +5 more administrators, and it only gives 4. I realize this is because them 'working' counts as one, and turning them into a Minister retires them to create a net of 4, it just would be nice if it was a little clearer.
Xeno Adaptation and Extreme Colonization techs both "Can Colonize Extreme Worlds. +1", with Adaptation also giving the Hospital. I'm not sure Extreme Colonization does anything, except allowing further progress down the tree.
I got a planet with Two Harmony Crystals, and one of them cannot be improved since the improvement is Unique.
To Add to the money issue, one turn the Thanalan offered me 100,000 BC to declare war on someone. Checking on them, they have 165,198 BC in their reserves. (http://i.imgur.com/xylEBAt.jpg)
Will add more later.