Well. its about barbarians as title suggest. Here are some WTFs about them:
All happening on diety difficulity, 2.02 b patch(might be a slight name mistake):
playing as America
arround 3500 bc - Egyptian civ destroyed (when u save a game name of game tells u what age u have

, so "not another year clock mod" isnt working perfectly, yers are "arround" couse i dont remember exact year)
arround 3200 bc - Persian civ destroyed - WTH
arround 2400 bc - Russian civ destroyed - WTH
arround 800 bc - Indian civ destroyed - another WTH
after india was "raped" i entered orld builder, and Egypy, Persia, Russia was raped by barbs. Thebes, Helispolis was barbs cities. Parsegade(or something close) was Barbarian, other Persian city lies in ruins. Moscow and St.Petersburg are barbs, 3rd russian city is ruins, St.Pettersburg is under attack by Bismark. Indian Civ Delphi, Calcuta are barbs, Lahore belongs to Mongols. Mongols or Barbarians finished the job, dont know who for sure.
arround 1000 ad - Mongols dies by the hand of Chaina and Japan (my galley contacted Japan, Chaina and Mogols, so i knew when war waged)
arround 1200ad - Best WTH in world... I accidently adopted Slavery... wanted to go Caste System as i resarched Coda of Laws quite late.... In Washington rebels rised... 2 stacks... 4 mace man... trechubert and 2 longbowmans... 20 population city changed into a ruin... like WTH ?!?
Barbarians strenght is astonishing. How ever there are 2 more bugs whith barbs, here they be:
1) Barbarians are moving their army. Mostly in Asia and Africa. Mongolian archer goes to Tibet, where he stacks whith Chaina archer and goes to Nubia or farer... Skirnishers go to Tatar... "moving" units does not attack cities, does not kill workers/settlers/greatpeaple, does not pillage improvements... Only makes ur Laborers work on other title than barb units is stationing. |They stop their marching at 1000 bc, about resarching Iron Working.
2) Barbarians "forbids" AI civs from using workers when Barbarian City or "moving" unit. So it works like this. Nubia is like never conquared, and Thebes does have like 2 workers and 10 slaves in garnison, and not even a road is made in Thebes radius. Same thing goes for Rome whitch has Carthage close, and Madrid whith the city in Northern Affrica.
Thats all i have whith "buggs" i found. Spain, Rome and Egypt has a hard life. Some goes for Moscow, but St.Pettersburg goes nicelly improved. Arabia, Assyria and Babylon when captured cant be "improved" by AI, couse of moving troops. And that strong barbarians "raping" Egypt, Persia and Russia at early stage. Not allways they do destroy a civ thou.
I REmeber when in 2.0 vers. Egypt and Mali was strongest AI civs in game... now they die quite fast