Inexplicable instant research times

[Vegard Pompey]

I've been playing Civilization 4 BtS with friends and two games in a row now one player has gotten a weird bug that lets him research any technology in one turn. His amount of beakers stays the same and he can research anything way faster than the amount should let him. Both times the bug occured sometime in the late middle ages to renaissance and both times it occured to the same player.

This bug has ruined two excellent games and I don't want to see it ruin another. Is there anything to be done about it?