From what I hear, they had to get it launched because a financial deadline was approaching. The launch of the observatory was initially delayed due to the tsunami. Perhaps this put some pressure to override some of the usual safety checks.
This is also the 3rd mission to fail to launch a high spectral resolution X-ray calorimeter instrument. The first failed due to not getting into the right orbit. The second failed because of a design flaw in the cooling chain, which caused all the coolant to escape. There was some pressure to get some observations taken ASAP after launch - perhaps that rushed checks too?