This happened again in a different game. I tried to modify the terms of the trade to circumvent the problem, but got another crash.
Here's the saved game that reproduces the problem. You have to deal with a couple of planet/ship items before the offer comes up, but it does keep coming up.
I hope this gets fixed soon, since we don't have any control over when the trade offers happen, and so far there's no way to circumvent it, it's a game ender.
