I just experienced a pretty dramatic bug with the latest version (downloaded this morning -- 4/18): I just won a cultural victory, and as the cinematic started, I hit escape. It brought me immediately to the desription of the culture victory, but superimposed on it was the continuing game screen (namely, the research acquired screen).
Every time I hit escape to get to the main menu, I could go back to the game, and for a moment, I was back into the game, and not at the victory screen. It lasted about half a second, and then the victory screen was once again superimposed over the game screen. During that time period, I was able to slowly click out of everything that happens at the beginning of the turn (build orders, research orders, news, etc), until I was to the ship-move phase. Once there, I was finally able to click Done on the victory screen, and move to the Metaverse screen. The metaverse screen was fine -- so superimposition.
However, when I got back to the opening menu screen (with the starbase and cinematic), it was also superimposed over my continuing game. I had to quit out of the game, and restart my computer, in order to get the superimposition to turn off.
~SDC~