Bug report 1: The AI thinks building a trade yard is a high priority, even over removing ruins. Furthermore, building trade yards seems to be a higher priority in 3.1.0 than in 3.0.0. As a result, the AI can wind up being ruins collectors:

Bug report 2: The AI is poor at waging war. In the above screenshot's game, even as a ghoul unit was creating ruins, the white-outline force sent a single levy unit to try and defeat their northernmost province's lion nest. They're also more than willing to send  a clearly insufficient force to attack a ghoul unit (levy only, equal or inferior numbers).

EDIT: Just after that image I took the empty land northeast of white-outline (carpe diem!) and exchanged maps with the blue-purple just northwest of white outline... who has four more ghoul units causing problems. Therefore...

Bug report 3: As of 3.1.0, the AI cannot handle ghouls.

LATE EDIT: I've seen that the AI obsessions vary. Sometimes they really want trade posts, sometimes they really want farms, but on multiple occasions I've seen an AI build the same building over and over in the same territory.

I'm getting some really rocky performance on the latest version. It's so bad that I'm having difficulty pausing. Save

thank you for finding this

If you need to take a break, take a break; we don't want a talented developer to burn out, especially when they're 100% of the staff!

I've actually thought of modding Bronze Age, but I'd have to juggle it with the other projects I work on.

Speaking of bug reports, I found a rare one.

See the eight-province red-yellow maskling tribe? The correct answer is "no", as that's actually two tribes with the same culture, same primary color, and same secondary color. They even have similar names (three-province Bloodcrusher Clan in the east, five-province Bloodcutter Folk in the west).

Yes, the odds of a match like this are very low, but obviously it can happen! ;)

Since today is the day for bug reporting:

• In the zoomed-out view, the brown coast is also four pixels too high; it's less apparent, but you can see it in the fog mismatch pic above.
• The subwindows List Armies and List Settlements (of the upper-left window) both have overlap issues, both with the upper-left and lower-left window. This is more apparent while hovering over the button that opens them.
• The subwindow Economy (of the upper-left window) lets you scroll to the right until all the provinces are scrolled off. Fortunately, all it does is look odd (and suggest there are more provinces when there aren't).

Also, I noticed some AI issues. This is not an outright bug, but while observing the AI play itself (Preview map) the AI made four errors: two minor, one major, and one catastrophic.

• It assumed a two unit army should attack a unit enemy army.... even if the one unit is 100% health and the two units are 5% and 15% HP.
  
• It kept moving an army that was starving and low HP, causing a couple units to die. This was post-battle, mind you, so the army was simply moving back to its capital (and therefore lost a couple units for nothing).
• It failed to deal with cults, so three out of four cults managed to overthrow the province (I think the fourth was actually prevented..... by bandits overthrowing the province, seeing as it was a new force but the ghul cult vanished, aside form a ghul unit wandering around).
• It failed to deal with whatever splits apart forces (running out of heirs, maybe?). The strongest force (~15 territories) spectacularly imploded into five different forces.

EDIT: There's one more graphical bug (which is probably easily fixable): when scrolling downwards, it takes too long for the next row of tiles to be drawn; as a result, there's a black bar on the bottom before they show up, whether zoomed in, zoomed out, or city view. The only exception is buildings in city view (including roads and under-construction buildings); they show up fine.

EDIT 2: I found another bug; after viewing the AI play itself, if you try loading a previous game, the cult viewing mode will not show any cult data. Oddly enough, the other viewing modes (standard, diplomacy, and happiness) are fine.