A few times, when 'purchasing' a building from the build order list, the result has been that my save is entirely wiped. This has happened three times, all while purchasing an item that's not in the 1 spot on the build order, I think they were all prisms. This doesn't happen every time though, and I have not managed to reproduce it reliably.
This is not a local wipe. I'm talking about the set user URL being zeroed out. The current save, all old saves, everything. If I can figure out more from testing, I'll update. In the meantime, I've learned the hard way to keep my exports in a txt file as well.
I'm using Firefox 24 (1.0 for linux) on Linux Mint 16, though I doubt it matters.
I did not have the save/ view URLs saved, only the set user URL, so I don't know if those were wiped as well.