look at the attached image which shows the problem. Today is 12/Sep/2012, column 9/9 so to speak.
The dates of tickets #12 and #13 are computed from today since they don't have fields.start and fields.finish set. The end date of #1 is computed from the end date of #13 because it also doesn't have its fields.finish set.
There is a set dependency that #2 requires #1 by fields.succ and fields.pred, respectively. And 2 has its fields.start and fields.finish explicitely set.
I expect that #1 has to end before #2 starts and as a result from that #12 and #13 have to start earlier. This means #13 actually must end on the start date of #2 , and this means 12 must start earlier than today.