Does the Habanero have input voltage monitoring? 12.8V is less than 7% out of spec for 12.0V, which most things should handle at least 10% tolerance.
I'd consider it might be an undervolt issue, either from bad or insufficient output capacitors in the PSU or from a poor connection in the edge connector. I prototyped a DPS-800 board but always had trouble keeping the edge connector in solid contact with the PSU output contacts. Could be when the VRMs fire up they're draining their input caps and putting a huge sudden current load on the DPS-800, which is undervolting and tripping from one of those reasons. It could be the PSU is providing ample current but the cables are either too thin or too long, or poor connector contact, such that line impedance (either from high resistance or inductance) is not allowing sufficient sudden current changes to make up the instantaneous load. I'd suggest tucking an at-least-1000uF capacitor on each 6-pin connector (slide it in to the contacts on the back of the cable-side connector) which will help buffer out brief current spikes like that at the device instead of at the PSU. If that's the issue it ought to help, otherwise I don't really know.

Not to be a shameless plug, but that's why we design our PSU boards with additional output capacitance and low-impedance screw terminals, and supply 16-AWG cables for good current handling.