Beta 4 Bug - Game freezes with Trade Routes? (Maybe)

It is hard to diagnose this bug since it simpy freezes the game and never comes back after ending a turn (no error message generated) but I have run into it probably 100 times so far. It seems to freeze whenever I am in good diplomatic standing with all other Civs, have many active trade routes and the computer has built too many freighters. The freighters will park outside my planet as though waiting for a tech discovery to allow them a new route. This will go on for hundreds of turns until finally the game will simply end a turn and never come back. the sound keeps playing, the mouse moves and sometime I can even select menu buttons but the turn cycle never finishes. I can reload 10 or 15 turns back and still run into it.

This bug is keeping me from seeing anything beyond the mid-game.