I've started a new game as Iberia with the updated files, and now the era-splash was correct. Well done.
I have researched a bit regarding the city-screen crashes (which still occurs), and this is what I found (you might already know some or all of this):
When a city is producing units, the negative construction from the Shaman doesn't have any effect - it only affects improvements.
In the attached save-file, the city of Borkeno has one citizen and produces two shields per turn. It is producing Granary, and I f I reassign the citizen to another tile (without turning him into a specialist first), it works fine. If I try to turn him into a specialist, the game crashes. If I change city-production to a unit, I can turn him into a specialist without having a crash.
This is also the case for Iruna, the other city with one citizen and two shields production.
Cadir has 3 citizens and is producin a unit, and when I turn all citizens into specialist there is no crash. If I first switch to producing an improvement, the game crashes when I try to turn the third citizen into a Shaman. Or: while the city is producing a unit, turn all citizens into Shamans. Then switch production to an improvement, and the game crashes.
To me it seems that the crashes occurs when the production reaches zero (maybe a division by zero-error when the turns to complete is calculated?). A solution in the one-citizen city cases might be to increase the shield-production in the city-center to two, but you have no guarantee that it won't reach zero when the city gets more citizens. At least I know how to avoid these specific crashes, but does the AI?