One thing that always causes me grief...
...is that I have a lot of tables that go wider than the display size - when you've got possibly a hundred columns in a table, it can be hard to view in the monitor width. Anyway, once the table exceeds the window boundary, the table layout rules should give up trying to squeeze it back in. Similar to the way lists used to operate in the IWE forums where the right shift would eventually mean that you get one word per line.
Not that this has anything to do with you current predicament... But it reminds me that the one column says use 100% while the other is not 0%... I've seen that method used not infrequently, but I still I'm not comfortable with it.
Edit Note: The other thing I wonder is whether specifying the width attribute in the style in the first column but doing it in the td attribute in the other is the problem. Will it work if they are both set in the same manner (i.e. both as width= or both as style='width:").
