MPM82504 x4 parallel for 400A design

When we use the 4x MPM82504 in paralle for 400A.
After CTRL enable. votlage rise to target voltage then drop around 68mV after ~8ms.

  • Ramp setting, we try 27mV, voltage drop disapear but ripple is 100mV
  • Ramp setting, 68mV/41mV both has drop situation

Is there anything we can do to mitigate this symptom?